Across the UK, many cities are implementing Clean Air Zones - or CAZ - as a way of lowering inner-city emissions. Not only do they work to help provide cleaner air, but they’ve also been introduced to promote ‘greener’ forms of transport such as cycling.

They’re becoming more commonplace, too, with a number of large cities putting in place their own Clean Air Zones. But what are they, how do they work and what else do you need to know about them? Here, we’ve got all of the facts you need to look out for.


What is a Clean Air Zone?

Clean Air Zones are designated areas of a city or urban area which restrict certain types of vehicles from entering for free. This is usually aimed at older and more polluting vehicles which have a bigger impact on emissions. There are both charging and non-charging zones, too, with the latter, as you might expect, not requiring any form of payment.

Clean Air Zones often have large signs showing that you’re entering the area, so you should be able to easily see when you’re driving into one. Plus, most Clean Air Zones allow you to pay for any charges you might incur via phone or online.

What types of Clean Air Zones are there?

Clean Air Zones are differentiated by a category ranging from A to D. A, for example, includes buses, coaches, taxis and private hire vehicles, while B adds in heavy goods vehicles to the mix. Move up to C and you’ll find minibuses included in the charge, while D basically covers everything, including cars. Some areas will charge certain types of motorcycles to enter, too.

Each of these vehicle types will be required to meet specific emissions standards. Buses, coaches and heavy goods vehicles must meet Euro VI, while vans, minibuses, taxis, private hire vehicles and cars must meet Euro 6 for diesel and Euro 4 for petrol. Motorcycles, meanwhile, have to meet Euro 3.

For the most part, cars registered after September 1, 2015 will meet Euro 6 diesel, while most of those registered after January 1, 2006, will meet Euro 4. However, you can check which standard your car meets online or inside your vehicle’s handbook.

How much does entering a Clean Air Zone cost?

How much you pay really depends on the city, so you’ll need to check beforehand. However, most require a daily charge. Birmingham, for instance, will charge non-compliant vehicles £8 per day, while the most polluting vehicles could see a charge of up to £50 to enter the zone.

CO2 Sign
clean air zone location sign

Which cities have Clean Air Zones?

Though there are a number of Clean Air Zones currently in place, only a few affect drivers of standard private cars. Here’s where you’ll encounter these zones.


Birmingham introduced its Clean Air Zone back in 2021. To enter with a non-compliant vehicle, drivers are required to pay £8 a day while owners of larger and heavier vehicles could see a charge of up to £50 per day.

As with many other Clean Air Zones electric and hybrid vehicles are exempt from the charge as a result of their lower emissions, as are motorcycles.


Bristol’s Clean Air Zone is one of the most recently introduced. Bristol City Council has, however, already stated that more than 71 per cent of vehicles entering the zone already meet the required standard.

However, for those people who drive a car which doesn’t meet these parameters, there’s a £9 daily charge which is the same for both diesel and petrol vehicles.


London’s Ultra Low Emission Zone - or ULEZ - is one of the most talked-about. Though it technically doesn’t fall under the Clean Air Zone umbrella, it still follows the same basic pattern of charging older, more polluting vehicles to enter. It costs £12.50 per day for non-compliant vehicles and motorcycles, while HGVs are hit with a £100 charge.

In October 2021, the ULEZ was expanded to the North and South Circular roads, however plans are already in place to increase its size even further so that it covers the entirety of the capital.


Oxford’s scheme is actually a zero-emissions zone - or ZEZ - and this means that only electric vehicles will be exempt from the charge. Any vehicles which don’t meet Euro 4 petrol or Euro 6 diesel cars will have to pay £10 per day.

However, even cars which do meet these standards will have to pay £4 a day and it’s expected that this price will increase from August 2025.



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