Press release: 25 November 2021

New data shows Bristol logged illegal pollution despite lockdowns 

New figures released by the UK Government and analysed by environmental law charity ClientEarth reveal that Bristol was one in a handful of cities in the UK that still charted air pollution levels above legal limits in 2020, despite several nationwide lockdowns.

The news comes as ClientEarth and the law firm Hausfeld are asking people whose health has been harmed by illegal pollution to come forward to join a new legal action.

The figures show that in 2020, nitrogen dioxide (NO2) pollution in Bristol was above the legal limit. The limit should have been met in 2010. Out of 43 air pollution reporting zones in the UK, Bristol is one of five – alongside West Midlands (which includes Birmingham), Greater London, South Wales and Greater Manchester – that exceeded it.

According to Bristol City Council, 300 premature deaths are linked to air pollution in the city annually. Dirty air is associated with a huge range of health issues including asthma, heart attacks, strokes and low infant birthweight.

Katie Nield, clean air lawyer at ClientEarth, said: “The data reveals that last year most of the UK recorded levels below the air pollution legal limits largely due to the restrictions caused by the Covid-19 pandemic but Bristol was one of the few exceptions. This should be a wake-up call for Bristol’s local leaders – the city has a serious air pollution problem that is not going to disappear on its own, urgent action is needed to protect people’s health.”

Road transport is the biggest source of NO2 in towns and cities across the UK contributing to up to 80% of illegal air pollution. The UK Government’s annual report on air quality largely attributes the low number of zones exceeding the legal limit in 2020 to the Covid-19 restrictions, which substantially reduced traffic activity on many roads – particularly during the first lockdown. However, by October 2020, traffic in Bristol had returned to above pre-pandemic levels. Meanwhile the Council was investigating postponing or weakening plans to tackle air pollution.

A Clean Air Zone (CAZ) was supposed to be introduced in October this year in Bristol – but has been pushed back yet again to summer 2022, after already being delayed several times. Analysis by Bristol City Council showed a Clean Air Zone to be the best way to quickly reduce illegal and harmful levels of air pollution in the city.

Other English cities like Birmingham and Bath have already followed through with their plans and introduced a CAZ earlier this year. Last month, London expanded its Ultra Low Emission Zone to cover an area 18 times bigger than the original area. The original ULEZ was shown to bring pollution levels down by 37%.

Nield added: “Other cities are already going ahead with Clean Air Zones to protect people’s health – local leaders in Bristol cannot delay any further the one measure that’s proven to reduce pollution. As part of this, our national government needs to pull its weight and assist Bristol City Council in quickly providing the help and support that people and businesses desperately need to move to cleaner forms of transport.”

People in towns and cities across the country – including Bristol – have little choice but to breathe illegally polluted air. Many people’s health will have already suffered as a result of government failures to tackle the problem. ClientEarth and the law firm Hausfeld are exploring a possible new kind of legal action against the UK Government to help people get the chance to push for change. People who think their health has been harmed by illegal pollution can express their interest online. Those wishing to learn more about the upcoming air pollution legal action can join a webinar hosted by ClientEarth and Hausfeld on 29 November.

Nield said: “This is a powerful new legal avenue to give people in places like Bristol the chance to push for change and get compensated for the harm they have suffered.”


Notes to editors:

Anyone wishing to learn more about the upcoming air pollution legal action can join a webinar hosted by ClientEarth and Hausfeld on 29 November.

In order to meet legal levels, a zone must have an annual average nitrogen dioxide (NO2) level at 40 µg/m3 or below. In 2020, the zones that were reported as over this legal limit were:

  • Greater London
  • West Midlands Urban Area (includes Birmingham)
  • Greater Manchester Urban Area
  • Bristol Urban Area
  • South Wales

Top 10 zones ranked by their reported annual mean NO2 concentration for 2020

Zone name

Exceedance of NO2 legal limit in 2020?

Annual mean NO2 concentration in 2020 (µg/m3)

West Midlands Urban Area



Greater London Urban Area



South Wales



Greater Manchester Urban Area



Bristol Urban Area



Nottingham Urban Area



Southampton Urban Area



South East



West Yorkshire Urban Area



The specific location for the exceedance in Bristol is on the A4044 on Bond Street near the corner with Stratton Lane (Grid Ref: 359435, 173510). The Council’s own monitoring data has also measured levels over the legal limit at other locations in the city.

Bristol City Council monitoring locations that recorded NO2 levels above the legal limit in 2020

Local authority monitoring location

Annual mean NO2 concentration in 2020 (µg/m3)

Type of monitoring

Colston Avenue


Automatic continuous monitor

Parson St. A38 East


Diffusion tube



Diffusion tube

Muller Rd/Glenfrome Rd junction


Diffusion tube


Air pollution tops the list of environment health hazards in the UK and is estimated to cause the equivalent of up to 40,000 early deaths a year nationally.

There is a growing body of evidence suggesting that there may be no safe level for NO2 (this is already accepted for fine particulate matter), with a recent study showing health impacts at levels below existing legal limits for NO2.

In September, the World Health Organization published its new guidelines on air pollution, reflecting the best available science on the health threats posed by toxic air. The organisation recommends that the concentrations of NO2 not exceed an annual mean concentration of 10 µg/m3 – the UK’s legal limit is four times higher.

ClientEarth has previously brought and won three cases in front of the courts in the UK – on these three occasions, the courts have found the UK Government to be breaching the law on NO2 pollution and have ordered ministers to produce new compliant air quality plans to tackle the problem.

About ClientEarth

ClientEarth is a non-profit organisation that uses the law to create systemic change that protects the Earth for – and with – its inhabitants. We are tackling climate change, protecting nature and stopping pollution, with partners and citizens around the globe. We hold industry and governments to account, and defend everyone’s right to a healthy world. From our offices in Europe, Asia and the USA we shape, implement and enforce the law, to build a future for our planet in which people and nature can thrive together.