New Delhi, (Hindustan Times), May 02, 2018 -  The Indian capital has once again been found to be the world’s most polluted city and Mumbai is fourth, according to air quality data compiled by the World Health Organisation (WHO) for megacities with a population of 14 million or more. Greater Cairo in Egypt is the second most polluted city, followed by the Bangladesh capital, Dhaka. Beijing ranks fifth.   

An analysis of particulate matter in the air showed about 90% of people across the world are exposed to bad air, which was linked to 7 million deaths in 2016, WHO found. Globally, ambient air pollution — caused by industries, cars and trucks, among others, caused 4.2 million deaths and indoor pollution caused 3.8 million deaths in 2016.