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ClientEarth Communications

12th March 2021

Air pollution

Cleaner air: coming to a UK city near you

Air pollution is damaging people’s health, reducing their quality of life and cutting lives short.

This is true all over the world – but we are seeing the start of a long-awaited change in the UK.

In 2019, 75% of UK air quality reporting zones were still charting illegal levels of air pollution, when legal limits should have been met in 2010. But after more than a decade of inaction, our hearts and lungs have something to look forward to. Concrete measures to get that illegal air pollution down – Clean Air Zones (CAZs) – are increasingly becoming a reality across the UK.

What are Clean Air Zones and why are they essential?

Following ClientEarth’s three court wins against the UK Government, ministers have ordered 63 local authorities to come up with proposals to tackle the illegal levels of pollution in their areas. Many of those with the biggest problems have put Clean Air Zones at the core of these plans.

CAZs deter the most polluting vehicles from entering the most polluted parts of towns and cities by setting minimum emission standards – those vehicles that do not meet these standards are discouraged from entering the zone by otherwise having to pay a charge. The UK Government’s own research shows that they are the most effective way to quickly reduce illegal and harmful levels of air pollution in urban areas – in short, they protect people, and quickly.

We know they work in practice: recent statistics show that London’s Ultra Low Emission Zone (ULEZ) has reduced nitrogen dioxide pollution by up to 37% in the 3-month period before the first lockdown, compared to a scenario where no ULEZ was in place.

Nitrogen dioxide – mainly coming out of vehicle exhaust pipes – is the main source of illegal air pollution in our towns and cities. Its levels have previously been up to double and even triple legal limits in many urban areas.

ClientEarth has always believed that the UK Government should introduce CAZs alongside help and support for people and businesses across the country to move to cleaner forms of transport as quickly as possible. This remains just as crucial now and should be part of the package of stimulus measures to help drive a green and healthy recovery.

Where are Clean Air Zones happening?


Launching on 15 March, Bath’s is the first Clean Air Zone outside of London. It will apply to all vehicle types that do not meet the minimum emissions standards except for private cars and motorcycles.

Sally Merrett, who lives in Bath, said:

I am really pleased that the Bath CAZ is coming into effect; it gives me hope that Bath will become an extremely attractive place to live, work and visit after many years of being blighted by air pollution.


Hot on Bath’s heels, Birmingham will be launching a CAZ affecting all vehicle types, including private vehicles, that do not meet minimum emission standards on 1 June.


Not to be outdone by its neighbour, Bath, Bristol City Council voted in February to approve plans for a CAZ in its city centre. The plans now have to be agreed by the government but the council is working towards launching the CAZ by the end of October of this year, which will be record time from the point of approval.

Expansion in London

In March, the capital tightened the emission standards for its city-wide Low Emission Zone, affecting buses, lorries, coaches and some vans, which has been in place since 2008. And crucially, the Ultra Low Emission Zone which launched in 2019 and applies to all vehicles including private cars and motorcycles, will be expanding from the city centre to cover all of inner London on 25 October.


Bradford Council has just approved plans for a CAZ in January 2022. Like Bath’s, it will apply to all vehicle types that do not meet the minimum emissions standards except for private cars and motorcycles.

You can check if your vehicle will be affected by any of the above CAZs at

Where next?

There are other major urban areas where CAZs are needed and may be launching soon. This includes Newcastle and Gateshead, Greater Manchester, Portsmouth, Liverpool and Leicester.

As more councils take action to tackle illegal air quality, the long-term benefits to public health and the economy will be huge and our cities will become better places to live.

However, this is not the end of the fight – we need to ensure that the UK government provides more help and support to people and businesses to move on to cleaner forms of transport, delivers a green and healthy recover and adopts stronger clean air laws to better protect people’s health.

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