Air pollution inequality widens between rich and poor nations

Rich cities have improved, but pollution in poorer countries is still rising and kills 7 million people a year globally, WHO data reveals

Pollution inequality between the world's rich and poor is widening, according to the latest global data from the World Health Organisation (WHO) which shows that 7 million people - mostly in developing nations - die every year from airborne contaminants.

Overall, nine in 10 people on the planet live with poor, even dangerous, air, says the WHO report, which is considered the most comprehensive collection of global air quality data. But levels of contamination vary widely depending on government actions and financial resources.