Delhi, Kolkata Among World's Top 10 Most Polluted Cities, Says Report. Check Details

"Of 7,239 cities, India is home to 18 of the 20 cities with the most severe increase in PM2.5 pollution from 2010 to 2019. The other two cities are in Indonesia," the authors noted in their findings

Delhi and Kolkata have been listed among the top 10 most polluted cities in the world in terms of exposure to hazardous fine particulate matter (PM 2.5), according to a report published by the US-based research organisation Health Effects Institute (HEI) on Wednesday. The report titled ‘Air Pollution and Health in Cities’ released by the HEI’s State of Global Air Initiative used data from 2010 to 2019 and focussed on two of the most harmful pollutants; fine particulate matter (PM 2.5) and nitrogen dioxide (NO2), reported news agency PTI.

Mumbai was listed in 14th position, and no other Indian city featured in the top 20. Around 18 of the 20 cities in India are found to have the most severe increase in fine particle pollutants (PM 2.5) from 2010 to 2019, according to a comprehensive and detailed analysis of air pollution and global health effects for over 7,000 cities.

"Of 7,239 cities, India is home to 18 of the 20 cities with the most severe increase in PM 2.5 pollution from 2010 to 2019. The other two cities are in Indonesia," the authors noted in their findings.

The report combined ground-based air quality data with satellites and models to produce air quality estimates for cities around the world.

How do other countries fare?

The report analysed the most populous cities in each region ie a subset of 103 cities across 21 regions. India and Indonesia witnessed the most severe increase in PM 2.5 pollution, whereas China has seen the greatest improvements.

"Of the 50 cities with the most severe increase in PM 2.5, 41 are in India and nine are in Indonesia. On the other hand, of the 20 cities with the greatest decrease in PM 2.5 pollution from 2010 to 2019, all are located in China," they said.

The report found that exposures to PM 2.5 pollution tend to be higher in cities located in low- and middle-income countries, while exposure to NO2 remains higher across cities in high-income as well as low- and middle-income countries.

"Since most cities around the world have no ground-based air quality monitoring in place, estimates of particulate and gas pollution levels can be used to plan air quality management approaches that ensure the air is clean and safe to breathe," said Susan Anenberg of George Washington University, one of the project collaborators, as reported by PTI.

In 2019, the author noted that 1.7 million deaths linked to PM 2.5 exposure occurred in the 7,239 cities included in the analysis. Cities in Asia, Africa, and Eastern and Central Europe saw the greatest health impacts during the year.

Going by the WHO's Air Quality Database, only 117 nations currently have ground-level monitoring systems to track PM 2.5, and only 74 nations are monitoring NO2 levels.

Globally, air pollution is responsible for one in nine deaths, accounting for 6.7 million deaths in 2019, with most impacts on the young, the elderly, and those with chronic respiratory and heart diseases, it said.