SmogRank / World / India / Tamil Nadu / January 2024

Most people breathing unhealthy air in Tamil Nadu, India, January 2024

1 city in Tamil Nadu, India measured at 2 or more places, ranked by how many people breathed unhealthy air on an average day over the 31 days. The most people breathing unhealthy air: Chennai, India, about 3.32M on an average day. A city needs measurements on 70% of the days to be ranked.

About 3.32M people in this city breathed unhealthy air on an average day of January 2024.

Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

All cities in the world, January 2024 · All cities in India, January 2024 · Tamil Nadu now

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SmogRank, most polluted cities in Tamil Nadu, India, by people breathing unhealthy air, PM2.5, January 2024, smogrank.com/in/region/tamil-nadu/history/2024-01?by=people (accessed 7 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.