Clean Air in London (“CAL”) has been fighting for clean air since 2006.
The legal, political and public health battle to reduce nitrogen dioxide (“NO2”), a toxic gas, and other pollutants is far from over.
Parliamentary Questions from Tim Farron MP (Liberal Democrat) have revealed that 16 cities and towns breached the NO2annual legal limit in 2023 and 12 won’t comply until 2026 – 2032. Newcastle won’t comply until 2045. These legal limits are four times higher than the World Health Organization’s (“WHO’s”) air quality guideline and twice the level set by Directive (EU) 2024/2881 to be achieved across Europe by 1 January 2030.
CAL submitted a formal complaint to the Office for Environmental Protection (“OEP”) on 17 July 2024 about Defra’s failure to comply with Air Quality Standards Regulations 2010. It also asked the OEP to take forward CAL’s complaint to the European Commission about the same exceedances that was closed finally and unresolved after more than 12 years on 24 April 2024. The OEP concluded on 9 May 2025 “that there may be ongoing serious failures to comply with environmental law” but “remaining reported exceedances are relatively isolated” and “We do not consider use of our enforcement functions would result in more rapid progress…”. The OEP’s letter “represents our final decision and there is no further right of review or appeal” (CMS-554). The OEP published summaries on 21 August[1] and 4 September 2025[2] without naming CAL.
Meanwhile, Defra has been revoking ‘air quality directions’ under the Environment Act 1995 and failing to enforce, update and add to existing ones[3]. In answer to another Parliamentary Question, they’ve listed local authorities with air quality plans to achieve compliance but failed to identify those without where compliance is also needed[4]. Frankly, it’s a shambles.
“CAL finds these legal breaches and the failures to take action totally unacceptable. CAL is calling therefore for the OEP to be scrapped (or preferably given new duties and powers) and Emma Reynolds MP, the new Secretary of State for Environment, Food and Rural Affairs, to pledge urgent compliance with air quality laws, including NO2 limit values and in the forthcoming EIP and Clean Air Strategy, and a new Clean Air Act. They must both be held accountable.
CAL is also calling for the government to support the Clean Air (Human Rights) Bill – Ella’s Law – proposed by Sian Berry MP (Green) to right these wrongs before the 70th anniversary of the first Clean Air Act on 5 July 2026. Last but not least, we need a new Parliamentary Select Committee ‘Super Inquiry’ on air quality.
Clean Air in London (“CAL”) has been campaigning for full compliance with World Health Organization (“WHO”) air quality guidelines throughout London and elsewhere for nearly 20 years.
CAL has used evidence, multi-channel communication and legal and political pressure to drive reductions in nitrogen dioxide (“NO2”) and particulate matter (“PM2.5” and “PM10”) since 2006. Its legal battles have focused mainly on NO2 because the limit values were almost identical to the WHO’s 2005 guidelines unlike PM10 which was twice the guideline. The WHO halved its air quality guideline for annual PM2.5 from 10 mg/m3 (micrograms per cubic metre of air) to 5 mg/m3 and slashed the guideline for annual NO2 from 40 mg/m3 to 10 mg/m3 on 22 September 2021.
The UK complied with the much weaker limit values for particulate matter (“PM10”) in 2012[5]. Shamefully, Mayor Johnson achieved compliance by using a ‘Pollution Suppressor’ to spray the road in front of key air quality monitors in London with ‘glue’ in the months before the London 2012 Olympics [6] i.e. rather than reducing emissions at ‘source’.
This article largely omits mention of PM2.5 and other pollutants, ClientEarth’s success in the Supreme Court and subsequently and the history the Great Smog, the current Clean Air Act and the Clean Air (Human Rights) Bill. Nor does it cover health evidence, policy solutions (such as low and ultra low emission zones, the phasing out of wood burning stoves and the need to reduce ammonia emissions from agriculture to reduce secondary PM2.5) or air pollution alerts during HIGH episodes. These topics are covered in detail elsewhere on CAL’s website and may be covered again in future articles.
Introduction
In the UK, the law on NO2 pollution – one of the most harmful pollutants – says annual average concentrations cannot exceed 40 µg/m3 (micrograms per cubic metre of air).[7]
That limit has applied but been breached in the UK since 1 January 2010 – yet the government now says it will not be achieved everywhere in England until 2045.[8]
The Office for Environmental Protection (“OEP”), set up post Brexit to replace the environmental enforcement role of the European Commission, has told CAL and the Government that the breach is potentially serious but has declined to enforce the law.[9] CAL is publishing the OEP’s Decision letter.
Given the lethal consequences of air pollution, and the recent confirmation that, on top of the environmental regulations, the government has the duty under Human Rights law to protect citizens from air pollution[10], the Secretary of State and the OEP are vulnerable to further legal challenge. Without effective action to clean up the air we breathe we are all vulnerable to air pollution-related disease and early death.
CAL’s legal fight for clean air
The legal history of the fight to reduce NO2 highlights how outrageous this government’s continuing breach of the law is, and how damaging to the enforcement of environmental law and to human health is the OEP’s refusal to take action.
Current law stems from ‘Directive 2008/50/EC on ambient air quality and cleaner air for Europe’ (the “AQD”) which established limit values for certain pollutants in ambient air. For NO2, the limit values were not to be exceeded after 1 January 2010.[11] However, if in a zone or agglomeration, in which conditions are particularly difficult, the limit values could not be met by that date notwithstanding the implementation of appropriate measures, a Member State could postpone the deadline until 1 January 2015 at the latest. That option was subject to the condition that the Member State drew up an air quality plan that demonstrated how the limit values would be achieved before the new deadline and by 1 January 2015 at the latest.
In 2014 legal questions about the UK’s non-compliance were ruled on by the Court of Justice of the European Union (“CJEU”)[12]. It said that where a Member State has not complied with the limit values and has not applied for a postponement of the deadline in accordance with the prescribed conditions (which the UK had not in 16 zones) it is for the competent national court to ensure that the state establishes a plan to ensure that the period during which the limit values are exceeded is as short as possible.
In its subsequent decision the UK’s Supreme Court ordered that the government must submit new air quality plans to the European Commission no later than 31 December 2015.[13] Further litigation arose from that requirement.
Meanwhile CAL was pursuing a parallel legal avenue. On 15 January 2012 it had complained to the European Commission about the UK’s failure to comply with air quality law. The complaint led to a CJEU decision on 4 March 2021 that the UK has “systematically and persistently” exceeded legal limits for dangerous NO2 since 2010 and has failed in its legal duties to put plans in place to tackle the problem in the shortest possible time.[14]
Had the UK remained in the EU that decision would have been enforced, for example through daily fines. The withdrawal agreement made provision for the enforcement of EU judgments by the EU for a limited period, but CAL was notified that the Commission no longer had the legal power to do so.[15]
CAL lodged a formal complaint therefore with the OEP on 17 July 2024 asking it to enforce the AQSR and consider CAL’s unresolved infraction case against the UK by the European Commission[16].
On 20 April 2021 the coroner’s report following the tragic death of Ella Roberta Addo-Kissi-Debrah caused by air pollution[17]notified the government that:
“…the national limits for Particulate Matter are set at a level far higher than the WHO guidelines. The evidence at the inquest was that there is no safe level for Particulate Matter and that the WHO guidelines should be seen as minimum requirements. Legally binding targets based on WHO guidelines would reduce the number of deaths from air pollution in the UK”.
The concerns, and the Government’s knowledge of them, suggests that government could be held liable not only for death and disease caused by NO2 which exceeds 40 µg/m3 but also for harm caused by air pollution which falls below the tighter standards recommended by the WHO since September 2021.
In October 2024, the case brought against the government by Ella’s mother was settled for an undisclosed sum and the government said it was “truly sorry” for Ms Adoo-Kissi-Debrah’s loss and that it was committed to delivering an “ambitious clean air strategy”.
Despite the apology, the government has singularly failed to ensure compliance with the law for over 15 years. Further, while the OEP was set up explicitly to fill the gap in environmental law enforcement left by Brexit – and called for the government to consider whether to bring standards more in line with WHO guidelines[18] – it has refused to use its powers to enforce the CJEU judgment or the AQSR. This is despite CAL pointing out that the government does not expect England to comply with current law in many zones until between 2026 – 2032 and 2045 and the current law permitting NO2 pollution four times higher than the WHO recommendations published in September 2021.[19]
The OEP’s quarterly report for the period 1 April – 30 June 2025 (dated 21 August 2025)[20], summarised their response to CAL’s complaint submitted on 17 July 2024 without naming CAL:
CMS 554 Compliance with Air Quality Standards Regs (2010) (May 2025)
We assessed a complaint and associated historic EU infraction cases in relation to reported exceedances of legally binding nitrogen dioxide air pollution limit values in England. We concluded that there may be ongoing serious failures to comply with environmental law. However, we do not consider use of our enforcement functions would result in more rapid progress as we found that national compliance trends are improving, and remaining reported exceedances are relatively isolated. We sought and received assurances that there are processes in place to address and monitor remaining exceedances. We agreed with Defra that we will continue to monitor the progress of the Joint Air Quality Unit and the Secretary of State in relation to this matter and scrutinise whether work is being effectively undertaken to close the remaining gaps in the implementation of the Government’s 2017 plan for tackling roadside NO2 concentrations. As part of our broader work programs, we will also continue to track and report on progress towards NO2 concentration limit values under the AQS Regulations, as well as NOx emission reduction commitments under the National Emission Ceilings Regulations 2018, within the framework of our Environmental Improvement Plan progress reporting. [CAL emphasis]
On 4 September 2025, the OEP published its Casework Summary Report for CMS-554 regarding ‘NO2 air pollution exceedances and alleged failures by the Secretary of State under the Air Quality Standards Regulations 2010 (AQSR)’ without naming CAL. It expanded on the above.
Based on information provided to us by [Joint Air Quality Unit], we understand that, as part of the Government’s 2017 UK plan for tackling roadside NO₂ concentrations, ministers directed 64 local authorities to consider measures to accelerate compliance with NO₂ limits in their respective areas. This has led to the introduction of measures in towns and cities across England aimed at reducing NO2 levels.
However, we found that there continue to be gaps in action to finalise and implement some of the resulting local authority plans. Our assessment found that several local authority NO₂ plans have still not been finalised and/or fully implemented in areas that continue to report exceedances. Our assessment also indicated that National Highway’s plans may not be fully finalised and/or implemented in areas where the SRN reports exceedances.
As a result, we concluded that there may be ongoing serious failures to comply with environmental law. Specifically, we determined that there is an indication that the Secretary of State may have failed, and be continuing to fail, to comply with their duties under Regulation 17 and 26 of the AQSR.
However, we do not consider use of our enforcement functions would result in more rapid progress in addressing these possible compliance failures. We found that national NO2 compliance trends are improving, and remaining reported exceedances are relatively isolated. [CAL emphasis]
Emma Reynolds MP replaced Steve Reed MP as Secretary of State for Environment, Food and Rural Affairs on 5 September 2025.
CAL finds these legal breaches and the OEP and Secretary of State’s failures to take urgent action totally unacceptable.
Quote:
Simon Birkett, Founder and Director of Clean Air in London, commented:
“Air pollution is the largest single environmental health risk[21].
“Defra’s failure to comply with the nitrogen dioxide (“NO2”) annual limit value for more than 15 years and estimates that it will take another five to 20 years are totally unacceptable.
“Further, the OEP’s unwillingness or failure to use its enforcement functions defies belief – particularly after CAL has highlighted expected legal breaches to 2026 – 2032 and 2045. It suggests that the OEP may have failed to fully understand the purpose, strength and wide applicability of ‘limit values’ and the right to life of those in so-called ‘relatively isolated’ locations. London has shown that limit values can be achieved much faster than expected.”
“These failures have been compounded by the Government’s disastrous ‘environmental’ strategy which has been a masterclass in diversion, channelling public outrage toward ‘nature recovery’ and water company scandals – such as unchecked sewerage spills – to shield it from scrutiny on other topics such as air pollution, human rights and the protection of public health. This is a great concern and must stop now.
“CAL finds these legal breaches and the failures to take action totally unacceptable. CAL is calling therefore for the OEP to be scrapped (or preferably given new duties and powers) and Emma Reynolds MP, the new Secretary of State for Environment, Food and Rural Affairs, to pledge urgent compliance with air quality laws, including NO2 limit values and in the forthcoming EIP and Clean Air Strategy, and a new Clean Air Act.
“They must both be held accountable.
“CAL is calling for the Government to support the Clean Air (Human Rights) Bill – Ella’s Law – proposed by Sian Berry MP and supported by many others, including in the next King’s Speech, to right these wrongs before the 70th anniversary of the first Clean Air Act on 5 July 2026.
“Last but not least, we need a new Parliamentary Super Inquiry to take forward the evidence produced for the Environmental Audit Committee’s inquiry into outdoor and indoor air quality targets in 2023 and the latest evidence from CAL.”
ENDS
About Clean Air in London:
Clean Air in London’s mission is to achieve full compliance, urgently and sustainably, with the World Health Organization’s air quality guidelines throughout London and elsewhere[22]. It was founded in 2006.
Notes:
- Annexes
Annex 1: Defra’s expected compliance dates for NO2 in zones in England (per Parliamentary Questions) together with localised hotspots, concentrations and ‘air quality directions’, if available.
Annex 2: OEP – Timeline of Clean Air in London’s legal battle to achieve compliance with WHO air quality guidelines including its formal complaints to the European Commission and OEP.
- Reassurances about the OEP’s role in 2018 and 2019
10 May 2018 Michael Gove (SoS, Defra)
19 December 2018 Michael Gove (SoS, Defra)
https://hansard.parliament.uk/Commons/2018-12-19/debates/18121943000015/25YearEnvironmentPlan
“[The OEP] will also offer a strong system of accountability, taking enforcement action where needed to make sure that government is delivering on its obligations under environmental law.”
Draft Environment (Principles and Governance) Bill, Statement of Impacts (December 2018)
https://www.gov.uk/government/publications/draft-environment-principles-and-governance-bill-2018
22 January 2019 Lord Kimble (Defra Minister of State, House of Lords)
Similar assurances were given by Theresa Villiers (SoS, Defra) on 15 October 2019 and George Eustice (SoS, Defra) on 4 March 2021.
https://hansard.parliament.uk/commons/2019-10-15/debates/19101540000015/EnvironmentBill
ANNEX 1
Defra’s expected compliance dates for NO2 in zones in England (per Parliamentary Questions)
N.B. Excludes England zones complying by 2023 and Northern Ireland, Scotland and Wales
| Compliance date and zone | Cities and towns | Hotspot (if different to city) and/or NO2 concentration measured in 2023 (mg/m3) |
| 2024 | ||
| Greater London | A201 City of London.A501 Westminster | 41.9; 41.6 (modelled value) |
| Nottingham | Ilkeston Road, Nottingham | 41.1‘Air quality direction’ (20 November 2018) required compliance ‘by 2019 at the latest’Note 1 |
| Reading/Wokingham Note 1 | Malcolm Place, Reading | 42.6Air quality direction (4 October 2018) required compliance by 2021 Note 2 |
| 2026 | ||
| Coventry/Bedworth | Holyhead Road, Coventry | 45.9‘Air quality direction’ (19 May 2021) required compliance ‘by 2021 at the latest’ Note 2 |
| Eastern Notes 1 and 3 | Southend Arterial Road, Basildon | 48.9‘Air quality direction’ (25 March 2021) required compliance ‘by 2022 at the latest’ Note 2 |
| Greater Manchester | A34 Bridge Street, A34 Quay Street, A664 Shudehill and Lever Street in Manchester.A49 Chapel Lane and King Street West, Wigan | ‘Air quality direction’ (4 February 2025) required compliance ‘by 2026 at the latest’ Note 2 |
| Portsmouth Note 1 | [Alfred Road], Portsmouth | 43.7. UIN 63555 shows Alred.Air quality direction (4 October 2018) required compliance by 2022 Note 2 |
| 2028 | ||
| South East Note 3 | A34 in the Vale of White Horse | |
| 2029 | ||
| Liverpool | Pembroke Place, Liverpool | 49.7‘Air quality direction’ (5 July 2021) required compliance ‘by 2024 at the latest’ Note 2 |
| West Yorkshire | Shipley Airedale Road, Bradford.Keighley | 47.8‘Air quality direction’ (12 February 2020) required compliance ‘by 2022 at the latest’ Note 2 |
| 2031 | ||
| Bristol | Colston Avenue, Bristol | 48.9‘Air quality direction’ (1 November 2021) required compliance ‘by 2023 at the latest’ Note 2 |
| Sheffield Note 1 | Brightside Lane, Sheffield | 48.8‘Air quality direction’ (13 July 2022) required compliance ‘by 2023 at the latest’ Note 2 |
| 2032 | ||
| The Potteries Note 1 | Etruria Road, Stoke on Trent | 58.4 |
| West Midlands | Moor Street Queensway and Prior Queensway in Birmingham | 51.5; 51.5.‘Air quality direction’ (11 March 2019) required compliance ‘by 2021 at the latest’ Note 2 |
| 2045 | ||
| Tyneside Note 1 | Stephenson Road A1058, Newcastle-upon-Tyne | ‘Air quality direction’ (7 December 2022) expected compliance will be achieved by 2023 Note 2 |
Notes
- Defra’s report titled ‘Air Pollution in the UK 2023 – Compliance Assessment Summary’ (September 2024) showed these zones as complying with the NO2 limit value in 2023[1].
- ‘Air quality directions’ and ‘revocations’ under Environment Act 1995 (section 85(5)) are published here:
Defra answer to UIN 45551 (17 April 2025) explained the reason for the difference[2]. Separately, UIN 45555 (17 April 2025) about exceedances within 10 miles of Heathrow Airport stated that local monitoring as part of the Local Air Quality Management (“LAQM”) process shows a small number of measurements about 40 mg/m3 at sites within a 10-mile radius of Heathrow Airport[3].
- Non-agglomeration zone.
- Limit values must be complied with throughout the territory of any given air quality zone with the only exceptions listed in Part 1, paragraph 2 of the Air Quality Standards Regulations 2010[4]. This requirement was transposed from Directive 2008/50/EC in Annex III (Section A, paragraph 2).
- Parliamentary answers
2024
Greater London – A201 City of London and A501 Westminster
UIN 63552 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63552
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Nottingham – Ilkeston Road
UIN 66554 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63554
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Reading/Wokingham – Malcolm Place, Reading
UIN 63556 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63556
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2026
Coventry/Bedworth – Holyhead Road, Coventry
UIN 63550 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63550
UIN 63559 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Eastern* – Southend Arterial Road, Basildon
UIN 63543 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63543
UIN 63544 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63544
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Greater Manchester – A34 Bridge Street, A34 Quay Street, A664 Shudehill and Lever Street, Manchester and A49 Chapel Lane and King Street West, Wigan
UIN 63553 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63553
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Portsmouth – [Alfred] Road. NB: UIN 63555 shows it as ‘Alred Road’
UIN 63555 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63555
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2028
South East* – A34 in the Vale of White Horse
UIN 63557 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63557
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 45558 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45558
UIN 45556 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45556
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2029
Liverpool – Pembroke Place
UIN 63551 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63551
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
West Yorkshire – Shipley Airedale Road, Bradford and Keighley
UIN 63549 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63549
UIN 63558 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63558
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2031
Bristol – Colston Avenue
UIN 63546 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63546
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Sheffield – Brightside Lane
UIN 63547 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63547
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2032
The Potteries – Etruria Road, Stoke on Trent
UIN 66127 – 9 July 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-07-09/66127
UIN 63548 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63548
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
West Midlands – Moor Street Queensway and Prior Queensway, Birmingham
UIN 63545 – 30 June 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-06-30/63545
UIN 45559 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45559
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
2045
Tyneside – Stephenson Road A1058, Newcastle-upon-Tyne
UIN 45553 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45553
UIN 39815 – 20 March 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-03-20/39815
Other
Heathrow – long list of local exceedances in PQ answer
UIN 45555 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45555
Gatwick
UIN 45554 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45554
Consistency between 2023 national compliance assessment and additional local monitoring data
UIN 45551 – 17 April 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45551
Local authority and Metro Mayor plans to achieve compliance with legal limits for nitrogen dioxide
UIN 66131 – 9 July 2025
https://questions-statements.parliament.uk/written-questions/detail/2025-07-09/66131
ANNEX 2
Timeline of Clean Air in London’s legal battle to achieve compliance with WHO air quality guidelines including its formal complaints to the European Commission and OEP
Background
Information about Commission decisions on infringement cases is available online:
https://ec.europa.eu/atwork/applying-eu-law/infringements-proceedings/infringement_decisions
INFR(2007)2184 on SO2 exceedances[1]
INFR(2008)2205 on PM10 limit values exceedances
INFR(2014)4000 on failure to fulfil obligations under Directive 2008/50/EC on nitrogen dioxide emissions
INFR(2017)0214 on several technical annexes to Directives 2004/107/EC and 2008/50/EC
INFR(2017)0243 on the reduction of national emissions of certain atmospheric pollutants
2006
9 April Letter to Mayor Livingstone asking whether his proposals for a low emission zone will go far enough, fast enough to comply with EU limit values for NO2 and PM10
10 May Letter to Commissioner Dimas seeking his commitment to protect Londoners from high levels of NO2, PM2.5 and PM10
2007
4 September European Commission sends UK Letter of Formal Notice in respect of breaches of EU legal limits for sulphur dioxide (SO2)
https://theecologist.org/2007/sep/04/europe-threatens-sue-uk-over-sulphur-dioxide-levels
2008
11 June Directive 2008/50/EC published in EUR-Lex and enters into force
https://eur-lex.europa.eu/eli/dir/2008/50/oj/eng
4 July Independent | ‘Simon Birkett: We’re choking to death while the government dithers’. NB this article referred to the importance of the ‘margins of tolerance’ laid down in Annex XI of Directive 2008/50/EC in accordance with Article 22(3) and Article 23(1).
2009
February Defra consultation to secure additional time to meet the limit values for PM10
Background to UK’s approach to NO2 time extension
https://cleanair.london/app/uploads/CAL-320-Defra-NO2-plans_February-2009.pdf
2011
9 June Defra launches consultation on air quality plans to meet NO2 limit values
https://assets.publishing.service.gov.uk/media/5a79cecbe5274a684690c3ee/consult-letter.pdf
https://www.gov.uk/government/consultations/air-quality-plans
11 June UK time extension on PM10 in London expires
https://uk-air.defra.gov.uk/library/annualreport/viewonline?year=2010_issue_3#report_pdf
4 August CAL letter to Secretary of State responding to consultation on air quality plans to meet NO2 limit values in 40 of 43 zones (with report showing 16 zones are expected to achieve compliance between 2015 and 2020 and the London zone is expected to achieve compliance before 2025)[2]
https://cleanair.london/app/uploads/CAL-166-Exhibit-3_Response-to-Defra-NO2-040811.pdf
September Government summary of consultation responses
13 December ClientEarth High Court judgment on NO2 breaches in Case CO/7207/2011 citation [2011] EWHC 3623 (Admin)
https://caselaw.nationalarchives.gov.uk/ewhc/admin/2011/3623?query=nitrogen+dioxide
https://assets.caselaw.nationalarchives.gov.uk/ewhc/admin/2011/3623/ewhc_admin_2011_3623.pdf
21 December Court of Appeal judgment in Birkett v Defra in Case C3/2011/1094 citation [2011] EWCA Civ 1606
https://caselaw.nationalarchives.gov.uk/ewca/civ/2011/1606?query=birkett
https://assets.caselaw.nationalarchives.gov.uk/ewca/civ/2011/1606/ewca_civ_2011_1606.pdf
22 December CAL letter to Defra re race equality impact assessments of plans to meet NO2 limit values
https://cleanair.london/app/uploads/CAL-166-Exhibit-4_Defra-reply-to-HG-re-REIA-2212111.pdf
2012
6 January CAL complains to Defra re belated PM10 consultation copying Commissioner Potocnik
15 January CAL submits two-part complaint to European Commission on PM10 and NO2
UK Compliance Assessment Summary for 2010
9 February European Commission acknowledges complaint with reference CHAP(2012)00246 – Letter
12 March European Commission letter to Jean Lambert MEP (Green)
19 March CAL calls for Secretary of State to resign (numerous references attached)
Commission letter to Jean Lambert MEP (Green) dated 12 March 2012 states:
“These [17] notifications were initially accepted by the Commission as notification made according to Article 22 of Directive 2008/50/EC. However, in light of the concerns raised by CAL and the information arising from the national court action by ClientEarth, the Commission is verifying whether it was correct to assess all notification received from the United Kingdom, including the one covering London, in accordance with Article 22.”
UK Overview Document (September 2011) titled ‘Air Quality Plans for the achieve of EU air quality limit values for nitrogen dioxide (NO2) in the UK’
See paragraph 1.1 on numbered page 7
https://uk-air.defra.gov.uk/assets/documents/no2ten/110921_UK_overview_document.pdf
“The UK is therefore submitting to the European Commission air quality plans with a view to postponement of the compliance date to 2015 where attainment by this date is projected.”
NB: A time extension was not possible in 17 zones because compliance was not projected by 1 January 2015
https://uk-air.defra.gov.uk/library/no2ten
1 May Consent Order signed by First-tier Tribunal following Birkett v Defra [2011] EWCA Civ 1606
30 May Court of Appeal judgment on NO2 breaches in Case No.: C1/2012/0010 in citation [2012] EWCA Civ 897
https://caselaw.nationalarchives.gov.uk/ewca/civ/2012/897?query=nitrogen+dioxide&court=ewca%2Fciv
https://assets.caselaw.nationalarchives.gov.uk/ewca/civ/2012/897/ewca_civ_2012_897.pdf
25 June European Commission decision – Published document
26 June European Commission letter to CAL closing CHAP(2012)00246 and transferring to EU Pilot file 3628/12/ENVI – Letter
12 August CAL letter to European Commission with supporting evidence e.g. pollution suppressor
20 August Defra letter to CAL re Complaint
11 September CAL letter to European Commission re Defra letter
2013
4 March UKSC blog | Simon Birkett: “Smog is expected to hang over the Supreme Court as it hears the most important air pollution case for a generation”
2014
20 February European Commission ‘starts’ infraction action on NO2
July Defra publishes ‘Updated projections for NO2 compliance’ showing that London, West Midlands and West Yorkshire would not comply with the NO2 annual limit value until ‘After 2030’
https://uk-air.defra.gov.uk/library/no2ten/index
10 July Supreme Court reference to Court of Justice of the European Union was heard before the CJEU with European Commission commenting. C-404/13 ex parte ClientEarth
1 August European Commission letter to CAL re letter addressed to UK on 21 February 2014 and UK reply on 16 April 2014. Separate letter to Keith Taylor MEP
19 November CJEU judgment in Supreme Court’s reference about ClientEarth case
https://curia.europa.eu/jcms/upload/docs/application/pdf/2014-11/cp140153en.pdf
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A62013CA0404
2015
29 April Supreme Court judgement re ClientEarth case
https://www.supremecourt.uk/cases/uksc-2012-0179.html
https://www.supremecourt.uk/cases/docs/uksc-2012-0179-judgment.pdf
https://www.supremecourt.uk/cases/docs/uksc-2012-0179-press-summary.pdf
3 August CAL Case Comment on Supreme Court judgement
2016
2 November High Court judgment in ClientEarth (No.2) vs SSEFRA, [2016] EWHC 2740 (Admin)
2018
21 February High Court judgment in ClientEarth (No. 3) vs SSEFRA [2018] EWHC 315 (Admin) in Case No.: CO/4922/2017
https://www.judiciary.uk/wp-content/uploads/2018/02/clientearth-no3-final-judgmentdocx.pdf
2019
March ClientEarth briefing for local authorities on duties by 15 September 2018, 31 December 2018, 30 June 2019 and 31 October 2019
2020
31 January UK leaves EU
31 December End of UK transition period
2021
4 March CJEU judgment in Case C-664/18 on NO2 breaches
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A62018CJ0664
2022
12 May Baroness Jenny Jones (Green) tops the ballot of Private Members Bills with the Clean Air (Human Rights) Bill which then completed all legislative stages in the House of Lords on 2 December 2022 before passing to Caroline Lucas MP
https://www.parliament.uk/business/news/2022/may-2022/lords-private-members-bills-ballot-2022
https://bills.parliament.uk/bills/3161
2023
September Defra’s publishes Compliance Assessment Summary for 2022
https://uk-air.defra.gov.uk/library/annualreport/index
2024
13 February European Commission letter to CAL about their intention to close off the complaint
11 March CAL letter to European Commission acknowledging their intention
24 April European Commission closes CAL complaint file
28 June European Commission writes to CAL confirming the position
1 July CAL writes to European Commission in acknowledgment.
1 July CAL email to OEP notifying them that the European Commission’s infringement file had been closed without resolution, the UK having left the European Union
3 July OEP email to CAL with information about its complaints and investigations process
4 July General Election in the UK
8 July OEP writes to new Defra Secretary of State and Ministers
17 July CAL letter to OEP submitting its complaint (first letter)
18 July OEP email acknowledges CAL’s letter of 17 July 2024
30 July Defra Secretary of State announces rapid review of EIP and publishes annual progress report 2023-24
31 July OEP meets Defra Secretary of State and Mary Creagh MP
22 August Defra Secretary of State writes to OEP
22 August OEP emails CAL ‘to update you on the status of [its] complaint submission’ (Unique ID: CMS-554)
9 September CAL letter to OEP (second letter) (Unique ID: CMS-554)
12 September OEP replies to Defra Secretary of State
12 September OEP emails CAL requesting further information by 11 October 2024
26 September Defra’s publishes Compliance Assessment Summary for 2023
https://uk-air.defra.gov.uk/library/annualreport/viewonline?year=2023_issue_1#report_pdf
https://uk-air.defra.gov.uk/library/annualreport/index
26 September CAL email to OEP drawing to its attention to Defra’s compliance summary
1 October OEP emails CAL saying it is considering complaint alongside two closely related workstreams
7 October CAL email to OEP requesting copies of its letters to Defra ministers on 8 July 2024
14 October European Council formally adopts directive setting updated air quality standards across the EU
https://environment.ec.europa.eu/topics/air/air-quality/revision-ambient-air-quality-directives_en
14 October OEP email to CAL requesting clarification on its information request on 7 October 2024
16 October CAL letter to OEP (third letter) (Unique ID: CMS-554) including formal information request
17 October OEP letter to CAL acknowledging its request for information (Ref No. EN-1243)
17 October Defra responds to CAL’s request for information: ‘Communication with the European Commission about INFR(2014(4000)’ that relates to Infringement case INFR(2014)4000 and/or the Judgment of the Court of Justice of the European Union in Case C-664/18 dated 4 March 2021 (Ref: EIR2024/18349) by releasing details
5 November OEP letter to CAL ‘Response to request for information’ (Ref No: EN-1243) enclosing correspondence between the OEP and Defra Secretary of State on 8 July 2024 and confirming that the Chair and Chief Executive of the OEP met the Defra Secretary of State and Mary Creagh on 31 July 2024 (and that the OEP does not hold agreed minutes of these discussions and NO2 limits were not specifically discussed during either of these meetings)
7 November CAL letter to OEP on unlawful exceedances of annual limit value for NO2 (their Ref No: EN-1243)
11 November OEP letter responding to CAL’s letter dated 16 October 2024 (Unique ID: CMS-554)
11 November CAL email to OEP requesting information about time scales (Unique ID: CMS-554)
13 November OEP email to CAL saying they ‘will endeavour to provide [CAL] with a substantive update [on its complaint] by 23 December’ (Unique ID: CMS-554)
25 November CAL letter to OEP responding to its letter dated 11 November 2024 (Unique ID: CMS-554)
27 November OEP letter to CAL responding to its letter of 7 November (Unique ID: CMS-554)
6 December OEP letter to CAL responding to its request for information (Ref No: EN-1243)
10 December Directive (EU) 2024/2881 on ambient air quality and cleaner air for Europe enters into force
https://eur-lex.europa.eu/eli/dir/2024/2881/oj
12 December CAL letter to OEP responding to its letter dated 27 November 2024 (Unique ID: CMS-554)
20 December OEP email to CAL saying that they would not be providing ‘an update by 23 December on your complaint’ and ‘look forward to talking again in early 2025’ (Unique ID: CMS-554)
2025
15 January OEP publishes report titled ‘Progress in improving the natural environment in England 2023/2024’
16 January Emma Hardy MP letter to CAL responding to its email of 28 December 2024 re AQIS Review and Directive (EU) 2024/2881
23 January CAL letter to DHCLG and Defra Secretaries of State re consultation on Planning Reform
24 January CAL email to OEP attaching CAL’s response to joint DHCLG and Defra consultation on Planning Reform’ and chasing progress on CAL’s complaint (Unique ID: CMS-554)
27 January OEP acknowledges receipt of CAL email of 24 January (Unique ID: CMS-554)
5 February CAL letter to Defra Secretary of State re ‘Interim statement on the EIP rapid review’
6 February CAL letter to OEP drawing their attention to the recent judgment of the ECHR (CASE OF CANNAVACCIUOLO AND OTHERS v. ITALY) and attaching CAL’s letter to Defra Secretary of State dated 5 February 2025
https://hudoc.echr.coe.int/?i=001-241395
24 February CAL letter to EAC re OEP
26 February Dame Glenys Stacey (OEP) gives oral evidence to EAC on the work of the OEP
https://committees.parliament.uk/event/23397/formal-meeting-oral-evidence-session
2 April CAL letter to OEP (Dame Glenys Stacey DBE) about its complaint and urging action. NB: Letter highlighted legal breaches expected until 2029, 2032 and 2045 (UIN 39815 and 41313)
9 May OEP decision letter to CAL titled ‘Complaint about the Secretary of State for Environment, Food and Rural Affairs and subsequent correspondence (Case Unique ID number: CMS-554)’
28 May Emma Hardy MP letter responding to CAL’s letter to Defra Secretary of State dated 5 February 2025
1 July Sian Berry MP (Green) introduces the Clean Air (Human Rights) Bill (under the Ten Minute Rule Bill)
https://bills.parliament.uk/bills/3998
12 July CAL letter to Defra Secretary of State about persistent and serious failures to comply, inter alia, with duties under Regulations 17 and 26 of the Air Quality Standards Regulations 2010’
11 August Emma Hardy MP responds to CAL’s letter to Defra Secretary of State dated 12 July 2025
21 August OEP publishes its quarterly ‘External Complaints Report (1 April 2025 – 30 June 2025)’ with reference to complaint ‘CMS-554 Compliance with Air Quality Standards Regs (2010) (May 2025)’. NB: CAL was not named.
https://www.theoep.org.uk/report/external-complaints-report-april-june-2025
4 September OEP publishes its Casework Summary Report for CMS-554 regarding NO2 air pollution exceedances and alleged failures by the Secretary of State under the Air Quality Standards Regulations 2010 (AQSR) NB: CAL was not named.
September Defra due to publish Compliance Assessment Summary for 43 UK zones and agglomerations for 2024
https://uk-air.defra.gov.uk/library/annualreport/index
[1] https://cleanair.london/legal/european-commission-takes-action-on-uk-breaches-of-air-quality-legal-limits/
[2] See section 1 paragraphs 1.1 to 1.3 on page 7 of Draft UK Overview Document dated June 2011
[1] https://uk-air.defra.gov.uk/library/annualreport/assets/documents/annualreport/air_pollution_uk_2023_Compliance_Assessment_Summary_Issue1.pdf
[2] https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45551/
[3] https://questions-statements.parliament.uk/written-questions/detail/2025-04-17/45555/
[4] https://www.legislation.gov.uk/uksi/2010/1001/pdfs/uksi_20101001_en.pdf
[1] https://www.theoep.org.uk/report/external-complaints-report-april-june-2025
[2] https://www.theoep.org.uk/investigation/no2-air-pollution-exceedances-and-alleged-failures-secretary-state-under-air-quality
[3] https://www.gov.uk/government/publications/air-quality-plan-for-nitrogen-dioxide-no2-in-uk-2017-air-quality-directions
[4] https://questions-statements.parliament.uk/written-questions/detail/2025-07-09/66131/
[5] https://uk-air.defra.gov.uk/library/assets/documents/annualreport/air_pollution_uk_2012_Compliance_Assessment_Summary.pdf
[6] https://cleanair.london/olympics/mayor-used-pollution-suppressor-to-save-himself-not-others/
[7] The law in England, derived from a European Directive, is now contained in Air Quality Standards Regulations 2010
[8] Parliamentary answers (see Annex 1)
[9] Refer to letter
[10] On 30 January 2025, the European Court of Human Rights (‘ECtHR’) handed down its judgment in Cannavacciuolo and Others v. Italy(“Cannavacciuolo”, nos. 51567/14 et al. 30 January 2025). The case is the first time that the ECtHR has found a violation of Article 2 of the European Convention on Human Rights (‘ECHR’) in a case concerning environmental pollution.
[11] Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe (OJ 2008 L 152, p. 1).
Court of Justice of the European Union
Luxembourg, 19 November 2014, Judgment in Case C-404/13
The Queen, on the application of ClientEarth v The Secretary of State for the Environment, Food and Rural Affairs
[13] R (on the application of ClientEarth) (Appellant) v Secretary of State for the Environment, Food and Rural Affairs (Respondent) [2015
[14] Case C-664/18, Commission v UK (Limit Values – Nitrogen Dioxide).
[15] https://www.legislation.gov.uk/eut/withdrawal-agreement/article/86
[16] Workstreams in OEP Corporate Plan 2023/24 to 2025/26 https://www.theoep.org.uk/sites/default/files/reports-files/OEP%20Corporate%20Plan%202023%2024%20to%202025%2026%20Accessible.pdf
[17] https://www.judiciary.uk/prevention-of-future-death-reports/ella-kissi-debrah/
[18] https://www.theoep.org.uk/report/government-has-chance-get-track-meet-legal-environmental-commitments-window-opportunity
[19] In 2021, the World Health Organization (WHO) revised its health-related air quality limit values, decreasing them to 5 μg/m3 for PM2.5 and 10 μg/m3 for NO2. According to analysis of data from 2021–23 on background air pollution, 96% of neighbourhoods in England and Wales are above the WHO guidelines for PM2.5 and 53% are above the guidelines for NO2.
[20] https://www.theoep.org.uk/report/external-complaints-report-april-june-2025
[21] https://www.bmj.com/content/381/bmj.p1037 and https://www.gov.uk/government/publications/health-matters-air-pollution/health-matters-air-pollution and https://www.gov.uk/government/publications/state-of-the-environment/state-of-the-environment-health-people-and-the-environment
