France, March 21 -- Cities contend with the worst air quality, thanks to traffic, industry and dense populations. Yet they are also the places where anti-pollution measures can produce the fastest and most visible results.

Breathe Cities analysed the strategies used by 19 major cities that have significantly reduced pollution levels. Cecilia Vaca Jones, executive director of the organisation, says cities can improve air quality faster than many people think.

RFI: What do the 19 cities that have been most successful in reducing air pollution have in common?

Cecilia Vaca Jones: First of all, all these cities do an excellent job collecting reliable data. That data helps guide policies and shows where anti-pollution action should focu...