The World Health Organization (WHO) released its list of the 20 most polluted cities in the world on May 2, which features 14 Indian cities. The air in Kanpur, Delhi, Varanasi, Patna and 10 other Indian cities is considered the most polluted according to data collated in 2016. Kanpur was the most polluted city on the list, followed by Faridabad. Varanasi ranked 3rd, while Gaya was 4th. Delhi occupied the 6th spot. Srinagar, Lucknow, Gurugram and Agra were some of the other cities that featured in the top 20. Bamenda in Cameroon, Peshawar, Rawalpindi, Kampala, Narayangonj and Doha were the six non-Indian cities on the list.
The ranking is based on the amount of fine particulate matter PM 2.5 in the air. According to WHO, PM 2.5 contains pollutants that pose the greatest risk to health. The South-East Asian and Eastern Mediterranean regions showed the highest levels of ambient air pollution.