World's Most Polluted Cities in 2024-25: Out of 138 countries and regions assessed, 126 (representing 91.3%) exceeded the World Health Organization's (WHO) annual guidelines for PM2.5 concentrations, the 2024 World Air Quality Report published by IQAir, recently highlighted. Notably, Central and South Asia host the world's top seven most polluted cities, with India being home to 13 of the 20 cities identified as the most polluted globally. Notably, Byrnihat, situated on the border of Assam and Meghalaya, has been identified as the most polluted city in the world, recording a staggering annual average PM2.5 concentration of 128.2 μg/m³, meanwhile, Delhi remains the most polluted national capital globally for the sixth consecutive year, with an average PM2.5 concentration of 91.8 μg/m³, as reported in the 2024 World Air Quality Report. In contrast, approximately 17% of global cities adhered to the WHO's air quality guidelines, with the Oceania region standing out as the least polluted area in the world for 2024, with its three countries maintaining annual average PM2.5 levels below the WHO's recommended limit. Top 10 most polluted global cities with the worst AQI in 2024-25 Rank City Country PM2.5 in 2024 1 Byrnihat India 128.2 2 Delhi India 108.3 3 Karaganda Kazakhstan 104.8 4 Mullanpur India 102.3 5 Lahore Pakistan 102.1 6 Faridabad India 101.2 7 Dera Ismail Khan Pakistan 93 8 N'Djamena Chad 91.8 9 Loni India 91.7 10 New Delhi India 91.6 Source: IQAir Methodology: The report has relied on data from 40,000 air quality monitoring stations across 8,954 locations in 138 countries, territories and regions, which has been analysed by IQAir’s air quality scientists. Here's the complete list of the top 20 most polluted cities in the world:
