SmogRank / World / India / Bihar / December 2025

Most polluted cities in Bihar, India, December 2025

21 cities in Bihar, India ranked by their average PM2.5 over the 31 days. Worst: Hājīpur at 92.4 µg/m³, #63 of 2,960 cities in the world. Cleanest: Kishanganj at 31.9. 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.

← Hājīpur 100% 75%0
Every city in Bihar, 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. 1Hājīpur
    100%
  2. 2Bihār Sharīf
    100%
  3. 3Arāria
    100%
  4. 4Patna
    100%
  5. 5Munger
    100%
  6. 6Buxar
    100%
  7. 7Arrah
    100%
  8. 8Rājgīr
    100%
  9. 9Katihar
    100%
  10. 10Gaya
    100%
  11. 11Muzaffarpur
    100%
  12. 12Bhāgalpur
    97%
  13. 13Mothīhāri
    93%
  14. 14Begusarai
    93%
  15. 15Purnia
    93%
  16. 16Saharsa
    89%
  17. 17Chāpra
    88%
  18. 18Bettiah
    83%
  19. 19Samāstipur
    83%
  20. 20Sasarām
    78%
  21. 21Kishanganj
    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

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SmogRank, most polluted cities in Bihar, India, PM2.5, December 2025, smogrank.com/in/region/bihar/history/2025-12 (accessed 6 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.