The most polluted cities in the world last year have been revealed in a new study, with countries in Asia dominating the top 10, a new study suggests.
Switzerland-based firm IQAir released its latest World Air Quality Report on Monday, which it said identified “alarming trends of the world’s most polluted countries, territories, and regions in 2024”.
This year’s report was based on analysis by IQAir’s air quality scientists of data from more than 40,000 air quality monitoring stations across 8,954 locations in 138 countries, territories, and regions, the firm said.
It focused on PM2.5, particles measuring 2.5 microns or less in diameter which are regarded as among the most dangerous pollutants to humans.
The air quality ranked countries and cities based on PM2.5 per cubic meter of air, using the benchmark of the World Health Organisation PM2.5 annual guideline (5 µg/m3).
According to the report, Byrnihat, an industrial town in India on the border of Assam and Meghalaya, was the most polluted metropolitan area of 2024, with an annual average PM2.5 concentration of 128.2 µg/m3.
India alone was found to have six of the nine most polluted global cities, a press release said, including Delhi, Mullanpur, Faridabad, and Loni.
Meanwhile, the country’s capital New Delhi was found to be the most polluted capital the world for the sixth consecutive year, with a PM2. 5 concentration of 91.8, as per CNN.
Two cities in Pakistan, Dera Ismail Khan and the country’s largest city Lahore also made the top 10.
Both India and Pakistan have struggled with smog in recent months, with experts blaming a combination of factors, including industrial emissions, exhaust from vehicles, crop burning, and dust from construction, as per Reuters.
Karaganda in Kazakhstan ranked third, with only city outside Asia being N’Djamena in Chad. The central African nation was also found to be the country with the worst air pollution.
Some countries, like Iran and Afghanistan, were not included in the report due to a lack of available data.
Frank Hammes, Global CEO of IQAir said: “Air pollution remains a critical threat to both human health and environmental stability, yet vast populations remain unaware of their exposure levels.
“Air quality data saves lives. It creates much needed awareness, informs policy decisions, guiding public health interventions, and empowers communities to take action to reduce air pollution and protect future generations.”
The top 10 most polluted cities by PM2.5 according to IQAir
- Byrnihat, India – 128.2
- Delhi, India – 108.3
- Karaganda, Kazakhstan – 104.8
- Mullanpur, India – 102.3
- Lahore, Pakistan – 102.1
- Faridabad, India – 101.2
- Dera Ismail Khan, Pakistan – 93
- N’Djamena, Chad – 91.8
- Loni, India – 91.7
- New Delhi, India – 91.6
You can find the full list here.