After one year of the zone, which is the second largest in England, GP visits for respiratory illnesses were down by a quarter

Bradford’s clean air zone has reduced air pollution and saved the health service about £30,700 a month in its first year, a study has found.

Low emission or clean air zones are often controversial, especially when they are first proposed. The expansion of London’s ultra-low emission zone became a major election issue, spawning disinformation, protest, vandalism and even the bombing of a traffic camera.