Wakefield council are actively breaching air quality rules.
That's according to statistics from DEFRA - the Department for Environment, Food and Rural Affairs - which shows the authority have breached the annual nitrogen dioxide limit value.
Andrea Lee, a healthy air campaigner from Client Earth, said: "In particular, nitrogen dioxide can irritate the respiratory system. So people with conditions such as asthma or COPD or emphysema will find themselves affected on a day to day basis.
"We are calling for a national network of clean air zones across the country, to help get the most polluting and dirty diesel vehicles out of our town and city centres."
40% of local authorities are breaking air quality regulations in Yorkshire.