SmogRank / India / Bihar / Arrah
Arrah, month by month
Arrah has a measured daily mean on 376 days since 19 February 2025. Its worst month was December 2025, at 164 US AQI (73.4 µg/m³), 95th of 3,006 cities on that month's world ranking. Its cleanest was September 2025, at 66 US AQI (17.4 µg/m³).
Every month since 2025
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
Months without a mean, and why
12 months
| Month | Why |
|---|---|
| Oct 2026 | 3 of 11 days measured; a month needs 8. The others: 4 with no readings from the monitor, 2 with readings for part of the day (a day needs 18 hours), 2 with readings left out by our checks. |
| Sep 2026 | 8 of 30 days measured; a month needs 21. The others: 4 with no readings from the monitor, 17 with readings for part of the day (a day needs 18 hours), 1 with readings left out by our checks. |
| Aug 2026 | 14 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 14 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | 19 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Mar 2026 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jan 2026 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Jul 2025 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Jun 2025 | 9 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| May 2025 | 13 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | 15 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 9 of 28 days measured; a month needs 20. The others: 1 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Arrah's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2025 | 16473.4 µg/m³ | 95thof 3,006 | – |
| November 2025 | 13950.9 µg/m³ | 168thof 2,715 | – |
| April 2026 | 10436.8 µg/m³ | 160thof 2,941 | – |
| February 2026 | 9532.6 µg/m³ | 219thof 2,866 | – |
| March 2025 | 8326.3 µg/m³ | 397thof 2,862 | – |
| May 2026 | 7421.3 µg/m³ | 262ndof 2,874 | Northern India, May 2026 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Arrah's worst days
| Day | US AQI | Episode |
|---|---|---|
| 7 Jul 2026 | 412281.0 µg/m³ | – |
| 8 Jul 2026 | 259184.0 µg/m³ | – |
| 26 Jun 2026 | 255180.0 µg/m³ | – |
| 12 Jul 2026 | 224149.0 µg/m³ | North-eastern India, July 2026 |
| 8 Dec 2025 | 199124.0 µg/m³ | – |
| 12 Dec 2025 | 192114.0 µg/m³ | – |
| 9 Dec 2025 | 189110.0 µg/m³ | – |
| 2 Jan 2026 | 189110.0 µg/m³ | – |
| 8 Jan 2026 | 187107.0 µg/m³ | – |
| 11 Dec 2025 | 17995.1 µg/m³ | – |
Daily means, the highest since 19 Feb 2025; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Arrah, India, 19 Feb 2025 – 7 Oct 2026. Monitor data from CPCB via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/in/arrah/history (accessed 12 Oct 2026).
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.
Arrah now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).