Sheffield has been named on a list of the most polluted towns and cities in the UK.
More than 40 places across Britain have exceeded air pollution limits set by the World Health Organization, a new report has found.
The WHO data shows 31 areas - including Sheffield - have fine particle air pollution levels above 10 micrograms per cubic metre.
However, the study also found that levels of pollution are dropping and the city's air is now cleaner than three years ago.
London and Manchester were also above the limit with the Welsh steelworks town Port Talbot named the worst.
Fine air particle pollution is particularly bad for humans, 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 report found that from 2013 to 2015 the total in Sheffield fell from 17 micrograms to 12.
Locally, other places that exceeded the limit of 10 micrograms per cubic metre were Scunthorpe (15), Leeds (12), Nottingham (12), York (12) and Hull (11).