2018 WHO ranking of polluted cities explained, bad news for India

The WHO reconfirms that several Indian cities have become death traps because of very high level of PM2.5 (particulate matter less than 2.5 micron size). Of the 20 most polluted cities in the world, the top 14 are in India. These include Kanpur, Faridabad, Varanasi, Gaya, Patna, Delhi, Lucknow,