SmogRank / World / India / Tamil Nadu / December 2025

Most unhealthy days in Tamil Nadu, India, December 2025

8 cities in Tamil Nadu, India ranked by their share of unhealthy days over the 31 days. The most unhealthy days: Gummidipundi, India, 26 of 27 measured days. A city needs measurements on 70% of the days to be ranked.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Gummidipundi 96% 90%0
Every city in Tamil Nadu, India ranked for December 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Gummidipundi
    26 of 27
  2. 2Neelankarai
    26 of 27
  3. 3Cuddalore
    25 of 26
  4. 4Karur
    21 of 25
  5. 5Coimbatore
    23 of 31
  6. 6Perundurai
    23 of 31
  7. 7Chennai
    22 of 31
  8. 8Naduvattam
    0 of 30
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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, December 2025 · All cities in India, December 2025 · Tamil Nadu now

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SmogRank, most polluted cities in Tamil Nadu, India, by unhealthy days, PM2.5, December 2025, smogrank.com/in/region/tamil-nadu/history/2025-12?by=days (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.