SmogRank / World / India / Bihar / May 2025

Most polluted cities in Bihar, India, May 2025

9 cities in Bihar, India ranked by their average PM2.5 over the 31 days. Worst: Hājīpur at 47.1 µg/m³, #40 of 2,771 cities in the world. Cleanest: Munger at 21.0. A city needs measurements on 70% of the days to be ranked.

About 1.28M people in these 3 cities breathed unhealthy air on an average day of May 2025.

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.

← Patna 987K 900K0
Every city in Bihar, India ranked for May 2025 with monitors in two or more places, one column each, ranked by people breathing unhealthy air: height is people on an average day, colour its average. Point at it to read a city; tap to open it.
  1. 1Patna
    987K
  2. 2Gaya
    229K
  3. 3Muzaffarpur
    61.1K
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, May 2025, smogrank.com/in/region/bihar/history/2025-05 (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.