Update 4 May 2018: This story, first published on 2 May, has been revised after the WHO issued corrected figures, including those that had originally put Port Talbot at the top of its list.
More than 40 towns and cities in the UK are at or have exceeded air pollution limits set by the World Health Organization, its new report has found.
The WHO estimates that 30 areas have fine-particle air pollution levels above 10 micrograms per cubic metre, with another 17 at that limit.
Areas that exceeded the level included London, Manchester and Swansea.
Dirty air can cause debilitating diseases and hasten death.
The figures on air pollution are contained in the WHO’s report, which estimates that globally nine out of 10 people breathe air containing high levels of pollutants.
Most of the UK figures were collected between 2013 and 2015 and in some places estimates of fine-particle air pollution were made based on measurements of larger particles of pollution.
In the UK, Scunthorpe had the highest estimated level of fine-particle air pollution at 15 micrograms per cubic metre, though this was from 2013.
Fine-particle air pollution is particularly bad for us, penetrating deep into the lungs and cardiovascular system, causing diseases including stroke, heart disease, lung cancer and respiratory infections, the WHO says.
It estimates that, globally, seven million people die each year from exposure to such pollution, with most of these deaths being in low and middle-income countries, mainly in Asia and Africa.
The world’s most polluted city in 2015, according to the WHO, was Muzaffarpur in India, with a figure of 197 micrograms per cubic metre – although that figure is under revision.
Pasakha in Bhutan, Delhi in India and greater Cairo, Egypt, also had very high levels.