CAZ Future Cities UK 2026: Which Areas Are Adding Zones

UK Clean Air Zones currently operate in London (ULEZ and LEZ), Birmingham, Bristol, Sheffield, Bradford, Portsmouth, Tyneside, Glasgow, Edinburgh, Aberdeen and Dundee. Several other cities have been studying CAZ implementation or have proposed schemes that may launch over the next several years. DEFRA's national Air Quality Plan, individual city NO2 monitoring data, and the legal duty under the Air Quality Standards Regulations 2010 to meet a 40 µg/m³ annual mean for NO2 drive the regulatory direction. This guide covers the cities most likely to add or expand emissions zones in 2026 and beyond, the typical implementation timeline, and the policy logic behind charging zones as the regulatory backstop.

Why some cities require CAZ and others do not

DEFRA's UK Air Quality Plan, originally published in 2017 and updated periodically, sets out cities where modelling indicated NO2 levels likely to breach the 40 µg/m³ annual mean legal limit. The original DEFRA list directed local authorities to prepare Clean Air Plans, with charging zones as the regulatory backstop where alternative measures could not deliver compliance. Some cities, including Birmingham, Bristol and Sheffield, implemented charging zones. Others, such as Leeds, met legal limits without a charging zone after improvements in fleet composition and traffic patterns. Manchester paused its scheme indefinitely.

The deciding factor is whether NO2 monitoring data at affected sites stays below the legal limit. Where it does, the city avoids charging. Where it does not, government can require a charging zone, with central government holding the legal duty for compliance with the regulations. Cities outside the original DEFRA list rarely need a CAZ, since their air quality typically already meets the limit.

Liverpool: studying CAZ options in 2026

Liverpool was identified by DEFRA as a city with NO2 hotspots and was directed to develop a Clean Air Plan. Liverpool City Council studied a CAZ Class C in 2020-21, focusing on the city centre and major arterial routes. The plan stalled and a final implementation date has not been confirmed in 2026. Liverpool City Region Combined Authority continues to monitor air quality data and consider implementation alongside broader transport investment.

If Liverpool moves ahead, the timeline from formal announcement to launch typically runs 18 to 36 months, factoring in public consultation, infrastructure procurement, ANPR camera installation, signage, payment portal development, and exemption administration. Drivers operating regularly in Liverpool should monitor the council's transport pages for any future CAZ announcement.

Cardiff and Welsh CAZ developments

Cardiff Council studied a CAZ as part of its compliance with Welsh Government air quality directions. The original proposal focused on the city centre and was paused while alternative non-charging measures, including bus retrofit and traffic management, were trialled. As of 2026, Cardiff has not implemented a charging zone but the option remains under review depending on future NO2 monitoring outcomes.

Welsh Government holds devolved powers over Welsh CAZ schemes, parallel to but distinct from English DEFRA-led arrangements and Scottish Transport Scotland-led LEZs. Drivers should expect any Welsh CAZ to follow Welsh Government rules rather than gov.uk/clean-air-zones, although the underlying Euro 6 diesel and Euro 4 petrol compliance test is likely to remain consistent across UK jurisdictions.

Scotland: Edinburgh, Aberdeen and Dundee already live

Scotland moved decisively to LEZ rollout in 2024. Edinburgh's LEZ moved to enforcement on 1 June 2024 covering the city centre. Aberdeen's LEZ also began enforcement on 1 June 2024 around Union Street and the central area. Dundee's LEZ moved to enforcement on 30 May 2024 covering the immediate central core. All three follow the same Scottish model as Glasgow: Euro 6 diesel and Euro 4 petrol compliance, doubling PCN structure capped at £480 for cars and £960 for commercial vehicles, motorbikes exempt.

Future Scottish LEZ expansion is not currently on the formal agenda, but Transport Scotland keeps monitoring air quality data and could direct further LEZ implementation if NO2 limits are exceeded elsewhere. Drivers travelling between Scottish cities should check lowemissionzones.scot before each journey.

Other cities watched: Belfast, Newcastle expansion, Nottingham

Belfast does not currently operate a CAZ, with Northern Ireland air quality policy devolved to the Department for Infrastructure. There is no announced CAZ scheme for Belfast in 2026. The Tyneside CAZ in Newcastle and Gateshead, active since 30 January 2023, may evolve in scope over coming years if monitoring data drives a need for tighter coverage. Nottingham was on the original DEFRA list but has not implemented a charging zone, focusing instead on bus retrofit and Workplace Parking Levy mechanisms.

Typical implementation timeline from announcement

A new CAZ typically takes 18 to 36 months from formal announcement to enforcement start. Public consultation runs 6 to 12 weeks. Final scheme design and Ministerial approval typically take 6 months. ANPR camera procurement and installation across boundary roads runs 6 to 12 months. Signage installation, payment portal development, exemption administration setup and a soft-launch grace period together account for the remainder. Drivers in candidate cities therefore have meaningful lead time to plan vehicle replacement.

Birmingham took roughly 36 months from initial DEFRA direction to its 1 June 2021 launch. Bristol moved over a similar timeframe before its November 2022 enforcement. Tyneside took about 24 months from final design to its January 2023 enforcement start. Scottish LEZs in Edinburgh, Aberdeen and Dundee compressed the timeline to roughly 18 months from formal scheme order to enforcement, helped by a single Transport Scotland framework that simplified design. Future cities can expect their own timeline to depend on whether they reuse existing scheme designs or develop new ones.

What drivers and fleets should do now

For drivers based in or operating into a candidate CAZ city, the practical preparation steps in 2026 are straightforward. Run every regularly used vehicle through the gov.uk vehicle checker to confirm Euro standard. For non-compliant vehicles, model the cost of a switch to a Euro 6 diesel, Euro 4 petrol or zero-emission alternative. Track the council's transport pages and DEFRA monitoring station data quarterly to spot early signals of scheme acceleration. Build CAZ exposure into vehicle replacement cycle planning rather than wait for an announcement that triggers a rushed decision.

For fleet operators with vehicles operating across multiple cities, the question is whether to standardise on Euro 6 diesel as the minimum spec across the entire fleet, removing exposure to any current or future CAZ. The arithmetic typically favours standardisation once two or three CAZ cities are part of regular routes. Battery electric vans, taxis and HGVs go further by removing both daily charge and PCN exposure permanently, regardless of how many new zones launch.

Frequently asked questions

Which UK cities are likely to add a CAZ next?

Liverpool and Cardiff are the most likely English and Welsh candidates respectively, both having studied CAZ proposals. Implementation depends on NO2 monitoring outcomes and political decisions by the relevant council and Welsh Government.

Will Manchester reactivate its CAZ?

Only if NO2 monitoring stations exceed the 40 µg/m³ legal limit, which would force government to require a charging response. The current GMCA position remains a non-charging Clean Air Plan with bus retrofit, taxi grants and infrastructure investment.

How much warning will drivers get?

Typically 18 to 36 months between formal announcement and enforcement start. Public consultation, scheme design, infrastructure installation and signage take that long even for cities with prior CAZ studies in hand.

Are CAZ rules consistent across the UK?

The Euro 6 diesel and Euro 4 petrol compliance test is consistent. The enforcement model differs: English CAZ uses daily charges, Scottish LEZ uses doubling PCN penalties, and London ULEZ uses a TfL-administered daily charge. Wales and Northern Ireland follow devolved rules.

Can I challenge a future CAZ before it launches?

Public consultations during scheme design provide the formal route for views to be considered. Judicial review remains theoretically possible but is rarely successful given the legal duty under the Air Quality Standards Regulations.

Where can I track new CAZ announcements?

DEFRA publishes annual air quality reports. Each candidate city's council transport pages typically host the scheme study and update notices. The gov.uk/clean-air-zones page is updated as new English zones come online.

Is the EV exemption likely to be removed in future zones?

No UK CAZ has signalled this in 2026. Removing the exemption would weaken the policy lever encouraging fleet electrification, and the air quality logic supporting EV exemption remains strong.

Sources

• DEFRA, UK Air Quality Plan and updates 2017-2025
• UK Air Quality Standards Regulations 2010
• UK Government, Clean Air Zones, gov.uk/clean-air-zones (accessed 2026)
• Transport Scotland, Low Emission Zones, lowemissionzones.scot (2026)
• Liverpool City Council, Clean Air Plan study reports (2020-2024)
• Cardiff Council, Air Quality plans and Welsh Government directions
• Greater Manchester Combined Authority, cleanairgm.com (2026)
• Edinburgh, Aberdeen, Dundee LEZ council enforcement statements (2024)

Internal links: Clean Air Zones UK overview · CAZ non-compliant vehicle options 2026 · Euro 6 vehicle CAZ compliance check 2026