Analysis commissioned by the Labour Party shows that 59% of UK residents are in areas where diesel pollution threatens health. Illegal levels of air pollution from diesel vehicles is seriously affecting nearly 40 million people in the UK.
Labour has called the air pollution issue a "national scandal". If elected, a Labour government would bring in a new clear air act to target the public health crisis, Sue Hayman, shadow secretary of state for environment, food and rural affairs said.
"Labour will not allow the Tories to use the snap general election or Brexit to kick this issue into the long grass or water down standards that would put millions of UK adults and children at risk."
The data shows that 59% of the British population (38 million people) is living in cities and towns where nitrogen dioxide (NO2) pollution is above the legal level of 40 microgrammes per cubic metre of air.
Other areas that have NO2 levels above the lawful level include Richmond, Aberdeen, Birmingham, Sheffield, Derby and Leeds.
The government made a last-minute appeal on Friday (21 April) to the high court in order to delay publication of a stricter air-quality plan to address the UK's air pollution problems, which was called a "public health emergency" by the environment, food and rural affairs (Efra) select committee.
James Thornton, chief executive of legal NGO ClientEarth, successfully took the Conservative government to court over its air quality plans.
"Our court case forced the government to come up with new plans to bring down illegal levels of air pollution across the country," he told the Guardian.
"Those plans must include a national network of clean air zones to keep the dirtiest diesel vehicles out of pollution hot spots, if we are to stand any chance of dealing with this public health crisis."
Nitrogen dioxide emissions from diesel traffic cause 23,500 of the 40,000 premature deaths from air pollution per annum, according to the Department for Environment, Food and Rural Affairs (Defra).
The EU is proposing to make cars, trucks, buses and vans pay a higher road toll charges if they emit more C02 emissions, according to Reuters.
The proposals are expected to be published on 31 May. After this date, they will need the approval of the European Parliament and other member states.