• Guides
  • Clean air zones explained

Clean air zones explained 2023

Phil Hall

Written by

Phil Hall

ULEZ sign Marble Arch London

Clean air zones are designed to tackle pollution and make the air we breathe safer in our cities. 

They are already in force in London in the form of the ULEZ (or ultra-low emission zone) which will become London-wide in 2023.

There are similar schemes in Bath, Birmingham, Portsmouth and Oxford (which has a zero emission zone pilot) with more cities planning to introduce them.

But what exactly is a clean air sone, why do they exist, what types do you get and how do they affect you as a driver? 

London ULEZ sign

What are clean air zones?

A clean air zone (CAZ) is an area where the local authority is actively trying to improve the quality of the air. Clean air zones were originally conceived to affect only buses, taxes and lorries, but the thinking has now expanded to include private vehicles in other words - the car you drive. It's part of the broader plan to improve air quality, which will see petrol and diesel cars phased out by 2030 with hybrid models' demise following five years later.

What types of clean air zones are there?

You'll come across two types of clean air zone – charging and non-charging.

Non-charging clean air zone will work to improve air quality without imposing tariffs on vehicles entering the zone. This can be done in a variety of ways such as improving traffic flow management and public transport networks. But also through government initiatives that advise on the health impacts of poor quality air, encourage the use of cycles and advise us to do things like switching our engines off when we're parked up.

It's the soft approach designed to change our attitudes towards air pollution, while gently steering us towards behaviour that lowers it. 

Clean air zones that charge take a more direct approach by simply charging any vehicle that's liable to enter the zone. This charge is usually based on your car's emissions, in London's ULEZ – which has a similar modus operandi to a CAZ – diesels that don't conform to Euro 6 and petrols that don't pass Euro 4 standards pay a fee. 

Classes of clean air zones

Charging clean air zones fall under four Classes – Class A, B, C and D. Class A covers buses, coaches and taxis, Class B effects buses, coaches, taxis, private hire vehicles and heavy goods vehicles, while Class C goes a step further bringing buses, coaches, taxis, private hire vehicles, heavy goods vehicles, vans and minibuses under its remit. 

Class D is the toughest of the lot covering buses, coaches, taxis, private hire vehicles, heavy goods vehicles, vans, minibuses and cars, plus the local authority has the option to include motorcycles.

Congestion Charge zone road markings

Why are clean air zones coming into force?

The Royal College of Physicians estimates that 40,000 deaths can be attributed to exposure to outdoor pollution. It has been linked to cancer, asthma, strokes, heart disease, diabetes, obesity and dementia. The knock-on effects to business and the national health service are said to cost the country more than £20 billion every year. 

Reports like this and pressure from environmental groups such as the World Health Organisation mean that government ministers were ordered by the Supreme Court to introduce measures designed to tackle the amount of nitrogen dioxide (NO2) in the air – clean air zones are central to this compliance. 

What are the clean air zones in the UK?

A number of cities in England such as Bath, Birmingham, Bradford, Bristol, Portsmouth and London have CAZs already operating, while others such as Sheffield and Tyneside are due to introduce them in 2023.  

Aberdeen low emission zone

Aberdeen introduced a low emission zone (LEZ) in May 2022. It is in the city centre as this is where air quality is poorest. Pre-Euro 6 diesel cars (generally those registered before 2015) and pre-Euro 4 petrol cars (generally those registered before 2006) will be fined £60 (reduced by 50% if paid within 14 days) if they enter the LEZ. However, there is a two-year grace period for all vehicle types to allow people time to comply with the LEZ. This means drivers with non-compliant vehicles will not be fined until mid-2024.

Bath clean air zone

Bath was the first city outside London to introduce a charging clean air zone. Its CAZ came into force in March 2021 and covers the city centre, operating 24 hours a day, 365 days a year.  Non-compliant vans, taxis and minibuses (pre-euro 6 diesel and pre-euro 4 petrol vehicles) are charged £9 per day to enter the zone. Trucks, lorries, buses and coaches, meanwhile, face a £100 daily charge. Private cars and motorbikes are currently exempt.

Birmingham clean air zone

Birmingham's Class D clean air zone took effect on 1 June 2021 and operates within the inner ring road (A4540 Middleway). Non-compliant cars, taxis and vans pay an £8 daily charge. Buses, coaches and HGVs that don't comply pay £50. It operate 24 hours a day, 365 days a year, with the charges applied daily to non-compliant vehicles.

Non-compliant vehicles driving in the Zone will pay once for the day, then may drive in the area without limit on that day. If your vehicle meets the necessary emission standards, you won’t need to pay the daily charge. For diesel cars, the standard is Euro 6 or better — while petrol cars will need a Euro 4 standard or better.  Fully electric or hydrogen fuel cell-powered vehicles won’t need to pay the charge.

Bradford clean air zone

Bradford clean air zone was launched on 26 September 2022. Non-compliant vans will be charged £9, non-compliant taxis £7 and non-compliant lorries, buses and coaches £50. There is no charge for private cars.

The Bradford zone covers the area inside, and including, the Bradford outer ring road. It also extends out along the Aire valley corridor, (Manningham Lane/Bradford Road and Canal Road area) to include Shipley and Saltaire.

Bristol clean air zone

Bristol's CAZ took effect on 28 November 2022. Private cars, taxis and vans will be charged £9 per day and buses, coaches and HGVs will be charged £100 per day. Owners of older vehicles will be able to apply for a one-year exemption.

Charges will not apply to: Euro 4, 5 and 6 petrol vehicles, roughly 2006 upwards; Euro 6 diesel vehicles, roughly end of 2015 onwards; fully electric vehicles and hydrogen fuel cell vehicles; modified or retrofitted vehicles registered with the Energy Saving Trust’s Clean Vehicle Retrofit Accreditation Scheme (CVRAS); and motorbikes.

Dundee low emission zone

Under current proposals, Dundee is due to introduce a low emission zone (LEZ) in mid-2022 with the inner ring road forming the boundary of the LEZ.

The Dundee LEZ will apply to all vehicle types, apart from motorcycles and mopeds. The minimum emission standards vehicles have to meet to enter the zone are Euro 4 for petrol cars and vans and Euro 6 for diesel cars and vans. Cars that don’t meet these standard and enter the Zone will be fined £60 (which can be reduced by 50% if paid within 14 days) . However, there will be a two-year grace period, which means enforcement will start for all vehicles in mid-2024.

The LEZ will operate 24 hours a day, 365 days a year.

Edinburgh low emission zone

Edinburgh will introduce a low emission zone (LEZ) on 31 May 2022, subject to final approval by the council and the Scottish Government in spring 2022.

The minimum standard for petrol cars and vans  is Euro 4 and for diesel cars, the standard is Euro 6 or better.

There will be a two-year ‘grace period’ before any penalty charges are issued, which means enforcement will not begin until 1 June 2024.

The proposed boundary for the Edinburgh LEZ is around the city centre and includes: the West End; Queen Street and the New Town; Greenside at the top of Leith Walk; Abbeyhill on the east; Pleasance; Meadows; Tollcross.

Glasgow low emission zone

Glasgow was Scotland's first city to introduce a low emission zone. The LEZ, which operates 24 hours a day, all year round, was introduced at the end of 2018 and currently only applies to local bus services. From June 2023, however, all non-compliant vehicles will be charged to enter the LEZ in the city centre. People who live in the zone will be granted an additional year (until 1 June 2024) to comply. The vehicle must be registered to a residential address within the LEZ zone area to qualify for this grace period.

Euro 4 petrol vehicles, Euro 6 diesel vehicles and electric vehicles are compliant with the Glasgow LEZ. Motorcycles, mopeds, motorised tricycles and quadricycles are unaffected by LEZ schemes in Scotland.

Greater Manchester clean air zone

Greater Manchester's clean air zone (CAZ) is currently under review. The scheme was due to be introduced on 30 May 2022, and would have applied to private hire vehicles, vans, buses and HGVs. However, concerns about financial hardship for local people and the availability of compliant vehicles led the Mayor of Greater Manchester and Greater Manchester local authority leaders to ask the Government to lift its legal direction for the CAZ to be introduced as soon as possible.

A new Government direction now requires Greater Manchester’s 10 local authorities to bring nitrogen dioxide on local roads to within legal limits as soon as possible and by no later than 2026.

Greater Manchester’s 10 local authorities have until 1 July 2022 to work with Government to develop a new plan that will clean up our air while protecting livelihoods.

Liverpool clean air zone

Liverpool is considering a clean air zone, as part of its Clean Air Plan. 

If it goes ahead it will be implemented in 2023 and the zone is likely to include the city centre where the highest levels of NO2 are. 

London ULEZ

The London ultra-low emissions zone (ULEZ) charges £12.50 per day for non-compliant cars, motorcycles and vans and £100 per day for heavier vehicles including lorries. These charges are payable in addition to the weekday congestion charge and low emission zone (LEZ) charge.

The ULEZ was extended to an area 18-times larger than the original zone in October 2021, encompassing London boroughs up to both the North and South Circular roads. 

The Mayor of London, Sadiq Khan, announced that the ULEZ will be expanded across all London boroughs from 29 August 2023.

Best cars that are ULEZ-exempt

ULEZ emissions boundary sign


Oxford launched a pilot zero emission zone (ZEV), which covers a number of streets in the city centre, on 28 February 2022, ahead of plans to introduce a larger ZEZ covering most of the city centre in 2023 (subject to a public consultation).

Drivers of petrol and diesel vehicles, including hybrids, have to pay a daily charge of up to £10 to enter the pilot zone, which operates from 7am to 7pm each day. 

The pilot covers New Road, between Bonn Square and its junction with Castle Street; Bonn Square; Queen Street; Cornmarket Street; New Inn Hall Street; Shoe Lane; Market Street, from Cornmarket junction east for 40 metres; Ship Street; and St Michael’s Street.

Zero emission vehicles, such as electric cars, can enter the pilot area free of charge, with cars that emit less than 75g/km of carbon dioxide (CO2) being charged £2, Euro 4 petrol and Euro 6 diesel cars attracting a £4 charge and all other cars having to pay £10. 

Newcastle, Gateshead and North Tyneside

A charging CAZ, which will cover most of Newcastle city centre, is due to be launched in July 2022. Tyneside's clean air zone will start charging on 30 January 2023

It will apply to taxis, vans, buses, coaches and HGVs that don’t meet national emissions requirements. 

For taxis and vans, this means Euro 6 diesel, registered after September 2015, and Euro 4 petrol vehicles, registered after 2005. For buses, coaches and HGVs this means Euro VI vehicles registered after 2014.

Charges for non-compliant vehicles to drive within the CAZ will be £12.50 a day for vans and taxis and £50 per day for buses, coaches and HGVs.

Private cars will not be affected by the CAZ.


Portsmouth’s clean air zone was introduced in November 2021 and is located to the southwest of the city. For the Portsmouth charging CAZ, non-compliant vehicles are Heavy Goods Vehicles (HGVs), buses and coaches, taxis and private hire vehicles (PHVs) that don't meet Euro 6 emissions standards (so are Euro 5 or older) if they are diesel or do not meet Euro 4 emissions standards (so are Euro 3 or older) if they are petrol. 

Older, more-polluting HGVs, buses and coaches pay £50 per day to travel through the zone and non-compliant taxis and private hire vehicles pay £10 per day. Private cars, motorcycles and vans are not charged under this Class B CAZ. 


Sheffield is introducing a charging CAZ in February 2023 , which will cover the inner ring road and the city centre, including Park Square and the A61/Parkway junction. 

The CAZ in Sheffield will not charge private cars for entering the city centre. Buses, HGVs and taxis are responsible for half of the air pollution but only make up 20% of traffic and, by focusing on them, the city can reduce air pollution as quickly as possible.

Vehicles that meet these standards would not be charged: Taxis which are ultra-low emissions (hybrid, electric and hydrogen fuel cell) or Liquid Petroleum Gas (LPG), LGVs and minibuses with Euro 6 diesel or Euro 4 petrol, buses and coaches with Euro 6 diesel, HGVs with Euro 6 diesel.

Vehicles that do not meet these standards would be charged: £10 per day for polluting LGVs and taxis and £50 per day for coaches, buses and HGVs.

Older diesel cars are taxed more heavily and some will be liable to pay emissions zone charges like London's ULEZ. Newer diesels are much cleaner and don't carry the financial penalties, however, they need regular motorway runs to keep their DPF filters clear. 

The UK government has pledged to ban the sale of petrol and diesel cars by 2030, with hybrid cars going off sale in 2035. While this covers the sale of new cars, it's not clear how these changes will effect cars that are already on the road.

If you're buying a second hand car that you'll drive in the London ultra low emission zone, which is set to expand London-wide in 2023, you'll want to choose a car that conforms to its regulations. In other words, you want a Euro 6 diesel (one sold from 2015 onwards) or a Euro 4 petrol, which were sold from 2005. Before you buy your car, you're best to check if it's exempt on the Transport for London website. 

heycar recommends

View all results