Where Data Tells the Story
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Oxygen is what keeps us alive. But air pollution is a serious issue in some parts of the world.
In observance of this year’s World Environment Day, celebrated on June 5, today’s visual presents the world’s most polluted cities, ranked by PM2.5 levels.
PM2.5 measures tiny airborne pollutants. Higher levels mean dirtier, more hazardous air that goes deep into the lungs and the bloodstream.
Central and South Asia were hardest hit overall.
Byrnihat, a border town between Assam and Meghalaya, is the world’s most polluted city in 2024, with an annual PM2.5 level of 128.2 µg/m³, more than 25 times the WHO limit.
For context, Delhi ranks second at 108.3 µg/m³, while India accounts for 11 of the top 20 hotspots.
With over 80 factories in the region emitting pollutants from cement, chemical, and pharmaceutical industries, air quality is poor.
Sheltering hills trap pollution, low rainfall prevents its dispersion, and traffic exacerbates the problem.