SmogRank / World / India / Bihar / September 2026

Most polluted cities in Bihar, India, September 2026

12 cities in Bihar, India ranked by their average PM2.5 over the 30 days. Worst: Bhāgalpur at 40.9 µg/m³, #52 of 2,949 cities in the world. Cleanest: Mothīhāri at 18.6. 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.

← Bhāgalpur 46% 40%0
Every city in Bihar, India ranked for September 2026, 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. 1Bhāgalpur
    46%
  2. 2Sasarām
    41%
  3. 3Arāria
    40%
  4. 4Begusarai
    38%
  5. 5Gaya
    27%
  6. 6Hājīpur
    23%
  7. 7Kishanganj
    20%
  8. 8Rājgīr
    9%
  9. 9Mothīhāri
    4%
  10. 10Patna
    0%
  11. 11Muzaffarpur
    0%
  12. 12Katihar
    0%
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, September 2026, smogrank.com/in/region/bihar/history/2026-09 (accessed 6 Oct 2026).

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