SmogRank / World / India / Bihar / 2025

Most polluted cities in Bihar, India, 2025

5 cities in Bihar, India ranked by their average PM2.5 over the 365 days; 5 above the WHO annual guideline (5.0 µg/m³). Worst: Hājīpur at 65.8 µg/m³, #16 of 2,624 cities in the world. Cleanest: Bhāgalpur at 39.1. 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 78% 70%0
Every city in Bihar, India ranked for 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
    78%
  2. 2Patna
    59%
  3. 3Gaya
    56%
  4. 4Bhāgalpur
    53%
  5. 5Muzaffarpur
    45%
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, 2025, smogrank.com/in/region/bihar/history/2025 (accessed 6 Oct 2026).

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