Gurugram in the National Capital Region was the most polluted city in the world in 2018, according to a new study by Swiss-based company IQAir AirVisual and non-profit organisation Greenpeace. The report said Delhi was the most polluted capital in the world.

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.

Credit: The 2018 World Air Quality Report

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.

Credit: The 2018 World Air Quality Report

“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.”

The report said data was sourced from a range of government monitoring sources. Data from a selection of validated outdoor IQAir AirVisual air quality monitors operated by private individuals and organisations have also been included. “The 2018 World Air Quality Report is based on the review, compilation and validation of data from tens of thousands of air quality monitoring stations around the world,” said IQAir Chief Executive Officer Frank Hammes in a statement.

It added that air pollution is likely to cause the death of around seven million lives globally in the next year, and will cost the world’s economy nearly $225 billion.