According to the World Air Quality Report 2024 by Swiss air quality technology company IQAir, Byrnihat in Assam is the most polluted city in the world, registering an average PM2.5 level of 128 µg/m³, while Delhi remains the most polluted capital city globally.
The high pollution levels in Byrnihat, an industrial town in northeast India located on the Assam-Meghalaya border, are due to emissions from local factories, distilleries, and iron and steel plants. Meanwhile, Delhi’s air quality deteriorated as a result of vehicular emissions, industrial pollution, paddy-straw burning, firecrackers, and unfavorable winter weather conditions.
Byrnihat recorded a PM2.5 concentration of 128.2 µg/m³ last year—more than 25 times the WHO’s standard.
As per the report published on Tuesday, thirteen of the world’s top 20 most polluted cities are in India, with six among the top ten.
The 13 Indian cities among the world’s 20 most polluted are Byrnihat (Assam), Delhi, Mullanpur (Punjab), Faridabad, Loni, New Delhi, Gurugram, Ganganagar, Greater Noida, Bhiwadi, Muzaffarnagar, Hanumangarh, and Noida.
Meanwhile, India ranked fifth in 2024, down from third in 2023, with the top four most polluted countries being Chad, Bangladesh, Pakistan, and the Democratic Republic of Congo.
Though India dropped from third to fifth place, the report stated that air pollution “remains a significant health burden… reducing life expectancy by an estimated 5.2 years.”
According to the report, the country saw a 7 percent decline in PM2.5 concentrations in 2024, averaging 50.6 µg/m³, compared to 54.4 µg/m³ in 2023.
In Delhi, which featured as the world’s most polluted capital for the sixth consecutive year, pollution worsened, with PM2.5 levels rising from 102.4 µg/m³ in 2023 to 108.3 µg/m³ in 2024.
The report also listed six satellite cities—Faridabad, Loni, Delhi, Gurugram, Noida, and Greater Noida.
The only city outside of Asia featured on the list is N’Djamena, the capital of Chad in central Africa, which was named the country with the worst air pollution.
The report by IQAir, a Swiss company that tracks global air quality, specifically focuses on fine particulate matter, or PM2.5, one of the smallest but most dangerous pollutants.
