Clean Air Zone

Clean Air Zone
White cloud symbol on a light green circle
Clean Air Zone traffic sign symbol
LocationSee § List of Clean Air Zones
Launched5 March 2021 (in Bath)

A Clean Air Zone (CAZ) is an area, such as a city or part of a city, where targeted action is taken to improve air quality. One definition is "a specified area in which vehicles are required to meet minimum emission standards." Action is often aimed at city transport. However some cities describe their general clean air program as a CAZ and the traffic part as a low-emission zone.

The main purpose of a CAZ is to reduce deaths and disease from air pollution. Other benefits may include increased productivity and road safety. Public consultation is key when trying to create a CAZ. When creating a CAZ public transport may be upgraded.

Breathe Cities is a collaboration between Bloomberg Philanthropies, Clean Air Fund and C40 Cities which supports cities to have cleaner air by helping with data, awareness, policymaking and co-operation between cities.

Benefits

Children's lungs may be healthier. Cardiovascular health may be improved. Workforce productivity may increase due to less sickness.

United Kingdom

Whether a vehicle is charged when entering or moving through a CAZ depends on the type of vehicle and the Euro standard of the vehicle. The amount charged is up to the local authority responsible for the CAZ. Ultra-low-emission vehicles are not charged when entering or moving through a Clean Air Zone.

Classes of charging Clean Air Zone

Class Vehicle Euro Category Charge applies to vehicles
below this Euro standard
Class A Bus
Coach		 M3 Euro VI
Taxi and private hire M2, M1 Euro 6 (diesel)
Euro 4 (petrol)
Class B Bus
Coach		 M3 Euro VI
Heavy goods vehicle (HGV) N2, N3
Taxi and private hire M2, M1 Euro 6 (diesel)
Euro 4 (petrol)
Class C Bus
Coach		 M3 Euro VI
Heavy goods vehicle (HGV) N2, N3
Taxi and private hire M2, M1 Euro 6 (diesel)
Euro 4 (petrol)
Minibus M2
Light goods vehicle (LGV) N1
Class D Bus
Coach		 M3 Euro VI
Heavy goods vehicle (HGV) N2, N3
Minibus M2 Euro 6 (diesel)
Euro 4 (petrol)
Light goods vehicle (LGV) N1
Taxi and private hire M1
Private cars
Motorcycles (optional)
Mopeds (optional)		 N/a Euro 3

List of Clean Air Zones

Operational
Region Type Date of implementation Scope Notes References
Bath Class C 15 March 2021 A wide central area Reduced nitrogen dioxide levels by 26% in 2022/2023, meeting legal standards.
Birmingham Class D 1 June 2021 All the roads within but not including the A4540 Ring Road
Bradford Class C+ September 2022 The area inside and including the Bradford outer ring road, extending to Shipley and Saltaire.
Bristol Class D 28 November 2022 A wide central area extending the North Somerset boundary, including the main route between Wales and Bristol Airport. Originally planned as class B with additional diesel vehicle ban in parts of city centre between 07:00 and 15:00. Changed to class D due to government rejection.
Derby Non-charging 2020 Traffic management measures on Stafford Street
Newcastle Class C July 2022 City centre, including bridges over the River Tyne and bridge approaches across the river in Gateshead
Nottingham Non-charging 2020 Retrofitting buses, regulating taxis, converting council-owned vehicles
Portsmouth Class B 29 November 2021 City centre area excluding port and naval base
Sheffield Class C 27 February 2023 Inner ring road and the city centre
Southampton Non-charging 2020 Retrofitting buses, regulating taxis, cleaner fuels and equipment at Southampton's port, cycling infrastructure
Planned or suspended
Region Type Scope Notes References
Greater Manchester Class B All local roads in the county Taxis and private hire vehicles registered within county exempt for first 12 months. Under review.
Leeds Class B City centre All roads within the boundary of the A61 and A63. Plans postponed in 2020 due to COVID-19 pandemic in England.
Leicester Class A Plans scrapped.

Other emission zones

Other LEZ in the UK
Region Type Start date Scope Notes/references
London LEZ 2008 Covers HGVs and buses around the

Greater London area
London ULEZ 2019 (expanded in

2021 and 2023)

 Covers all other vehicles in the same

area as the LEZ
Oxford ZEZ 2022 Covers all non-electric vehicles in the city centre.

Operational 07:00 to 19:00 including Sundays
Glasgow LEZ 2018 (expanded to

cars in 2023)

 Covers the city centre

Notes

  1. 1 2 3 4 5 6 7 8 Gross Vehicle Weight (GVW) more than 5,000 kilograms (5.0 t) and carries 8 or more passengers.
  2. 1 2 3 Goods vehicles with a Gross Vehicle Weight (GVW) over 3,500 kilograms (3.5 t).
  3. 1 2 Gross Vehicle Weight (GVW) less than 5,000 kilograms (5.0 t) and carries 8 or more passengers.
  4. 1 2 Goods vehicle with a Gross Vehicle Weight (GVW) under 3,500 kilograms (3.5 t).
  5. ↑ the initial ULEZ covered the same area as the congestion charge zone before expanding to cover the areas within (but not including) the A406/A205 in 2021. This was later expanded to cover the same area as the LEZ in 2023
  6. ↑ First zero emission zone in the UK
  7. ↑ Unlike other LEZ/CAZ schemes, non-complaint vehicles cannot pay to enter Glasgow's LEZ and will be fined £60.

References

  1. 1 2 Bath's Clean Air Zone: Annual report summary 2021 (PDF). Bath: Bath & North East Somerset Council. 16 June 2022. p. 3. Archived from the original (PDF) on 27 August 2023. Retrieved 27 August 2023.
  2. ↑ "Clean Air Zones in Asian Cities: Lessons and Reflections". Clean Air Fund. Retrieved 10 September 2026.
  3. ↑ "C40 Knowledge Community". www.c40knowledgehub.org. Retrieved 10 September 2026.
  4. ↑ "Clean Air Zone Framework" (PDF). DEFRA and DfT. May 2017.
  5. 1 2 3 "Clean Air Zones: Practical Guidance for Cities" (PDF). Some cities define their wider clean air programme as a CAZ, which could include a LEZ as a centrepiece.
  6. ↑ Erekat, Ala'; Okour, Yasmein (12 January 2026). "Challenges and opportunities of clean air zone planning: a case study of Amman, Jordan". Frontiers in Sustainable Cities. 7. Frontiers. doi:10.3389/frsc.2025.1696698. ISSN 2624-9634.
  7. ↑ "Who we are". Breathe Cities. Retrieved 11 September 2026.
  8. ↑ "What we do". Breathe Cities. Retrieved 11 September 2026.
  9. ↑ "London's clean air zone linked to improvement in children's lung health".
  10. ↑ "Bradford clean air zone brings £180m health benefits - study". www.bbc.com. 18 December 2025. Retrieved 10 September 2026.
  11. ↑ "Cleaner air in cities benefits health and the economy". CBI. Retrieved 10 September 2026.
  12. ↑ "Bath's Clean Air Zone". Bath and North East Somerset Council.
  13. ↑ Barltrop, Paul (25 August 2023). "Bath air quality improves since introduction of clean air zone". BBC News. Retrieved 26 August 2023.
  14. ↑ "A clean air zone for Birmingham". Birmingham City Council.
  15. ↑ "Clean Air Zone timing and charges | A clean air zone for Birmingham | Birmingham City Council".
  16. ↑ "Bradford Clean Air Zone to start in January 2022". BBC News. 2 March 2021.
  17. ↑ Cork, Tristan (6 July 2022). "Clean Air Zone start date finally announced". Bristol Post. Retrieved 22 August 2022.
  18. ↑ Rob. "CHARGES". Clean Air for Bristol. Retrieved 1 September 2021.
  19. ↑ "Derby submit Outline Business Case to government which confirms no CAZ". Air Quality News. 5 March 2019.
  20. ↑ "Latest delays to Newcastle Clean Air Zone pollution tolls 'condemning more of us to early deaths'". The Northern Echo. 26 July 2021.
  21. ↑ "GClean air zone proposals". Sheffield City Council.
  22. ↑ "Charging Clean Air Zone". Portsmouth City Council.
  23. ↑ "Clean air zone proposals". Sheffield City Council.
  24. ↑ "Clean Air Update". Southampton City Countil. January 2019. Archived from the original on 6 November 2019. Retrieved 6 November 2019.
  25. ↑ "Greater Manchester Clean Air Plan proposals". Clean Air GM.
  26. ↑ "Greater Manchester delays CAZ until 2022". Air Quality News. 21 May 2020.
  27. ↑ "GMCA 210621 Report Clean Air Plan" (PDF). GMCA. 25 June 2021.
  28. ↑ "Air Quality". Leeds City Council.
  29. ↑ "Leeds Clean Air Zone suspended for the foreseeable future". Air Quality News. 19 August 2020.
  30. ↑ "Leicester CAZ plans scrapped". Air Quality News. 6 April 2021.
  31. ↑ "Glasgow's Low Emission Zone". Glasgow City Council. Retrieved 30 October 2024.