The report measured the levels of PM2.5 - fine particulate matter of a diameter of 2.5 micrometres in the air - in 2018. PM2.5 is a pollutant that can fester deep in the lungs and bloodstream of humans.
Seven of the top 10 polluted cities in 2018 were in India, including Ghaziabad, Faridabad, Bhiwandi, Noida, Patna and Lucknow. Delhi ranked 11 on the list of polluted cities, with an average PM 2.5 concentration in 2018 at 113.5 micrograms per cubic metre.
The 2018 World Air Quality Report was based on information from over 3,000 cities."The city ranking shows Asian locations dominating the highest 100 average PM2.5 levels during 2018, with cities in India, China, Pakistan and Bangladesh occupying the top 50 cities," the report said.
The report showed Bangladesh was the most polluted country on average, closely followed by Pakistan and India. Afghanistan, Bahrain, Mongolia and Kuwait were among the top 10. Countries such as Iceland, Finland, Australia, Estonia and Sweden were among the least polluted.
"This [air pollution] has enormous impacts, on our health and on our wallets," said Executive Director of Greenpeace Southeast Asia Yeb Sano in a statement. "In addition to human lives lost, there's an estimated cost of $225 billion in lost labor, and trillions in medical costs."
