SmogRank / India / Bihar / Chāpra

Chāpra, month by month

Chāpra has a measured daily mean on 345 days since 19 February 2025. Its worst month was December 2025, at 156 US AQI (62.9 µg/m³), 135th of 3,006 cities on that month's world ranking. Its cleanest was May 2025, at 87 US AQI (28.2 µg/m³).

Every month since 2025

2026too few days for a mean (a year needs 200)148 days measured
Jan16 daysFeb18 daysMar21 daysApr18 daysMay12 daysJun11 daysJul14 daysAug19 daysSep16 daysOct3 days
2025too few days for a mean (a year needs 256)197 days measured
JanFeb2 daysMar17 daysApr10 daysMay87#161Jun19 daysJul9 daysAug108#41Sep136#15Oct18 daysNov102#228Dec156#135
Each square is a month's mean PM2.5 in US AQI from Chāpra's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Chāpra marked; each year, the year's.
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

Months without a mean, and why

16 months
MonthWhy
Oct 20263 of 12 days measured; a month needs 9. The others: 7 with no readings from the monitor, 2 with readings for part of the day (a day needs 18 hours).
Sep 202616 of 30 days measured; a month needs 21. The others: 7 with no readings from the monitor, 7 with readings for part of the day (a day needs 18 hours).
Aug 202619 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Jul 202614 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Jun 202611 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks.
May 202612 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Apr 202618 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks.
Mar 202621 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Feb 202618 of 28 days measured; a month needs 20. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jan 202616 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Oct 202518 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jul 20259 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Jun 202519 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Apr 202510 of 30 days measured; a month needs 21. The others: 20 with under 18 hours of readings or readings that failed our checks.
Mar 202517 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Feb 20252 of 28 days measured; a month needs 20. The others: 8 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.

Chāpra's worst months

MonthUS AQIDays measuredWorld rank
December 2025 15662.9 µg/m³25 of 31135thof 3,006
September 2025 13649.9 µg/m³23 of 3015thof 3,104
August 2025 10838.2 µg/m³28 of 3141stof 2,901
November 2025 10235.8 µg/m³23 of 30228thof 2,715
May 2025 8728.2 µg/m³23 of 31161stof 2,826

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.

Chāpra's worst days

DayUS AQIEpisode
1 May 2026 269194.0 µg/m³–
24 Apr 2026 216141.0 µg/m³Eastern India, April 2026
8 Dec 2025 201126.0 µg/m³–
12 Dec 2025 198123.0 µg/m³–
4 Sept 2025 192114.0 µg/m³–
9 Sept 2025 18096.6 µg/m³–
13 Sept 2025 17995.0 µg/m³–
11 Dec 2025 17994.8 µg/m³–
11 Mar 2026 17792.8 µg/m³–
3 May 2026 17691.1 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, Chāpra, India, 19 Feb 2025 – 7 Oct 2026. Monitor data from CPCB via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/in/chapra/history (accessed 12 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.

Chāpra now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 22:07 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).