SmogRank / India / Bihar

Air quality in Siwān

Bihar, India. PM2.5 from 1 reference monitor, updated hourly.

26.4 µg/m³
Moderate

Mean for 28 Sept, the most recent day with readings, 1.8× the WHO 24-hour guideline. No hourly readings have reached us since; some networks publish days late.

Rank

24 h
–
not enough data
7 days
–
not enough data
30 days
–
not enough data
Year
–
not enough data

Why it ranks here

Chronic pollution. Its typical day over the past year was 41.2 µg/m³, 2.7× the WHO 24-hour guideline, so it ranks high most of the time, not only during events.

Based on Siwān's own measurements; causes are the usual kinds for a pattern like this, not a confirmed source.

Hour by hour

No hourly readings in the last few days. The chart returns when the monitors' data arrives.

Every day for a year

SepNovDecJanFebMarAprMayJunJulAugSepMonWedFri2025-09-29: 37.4 µg/m³2025-09-30: 30.5 µg/m³2025-10-01: no data2025-10-02: no data2025-10-03: no data2025-10-04: no data2025-10-05: no data2025-10-06: no data2025-10-07: 29.1 µg/m³2025-10-08: 30.7 µg/m³2025-10-09: 28.5 µg/m³2025-10-10: 36.2 µg/m³2025-10-11: 37.2 µg/m³2025-10-12: 40.6 µg/m³2025-10-13: no data2025-10-14: 56.8 µg/m³2025-10-15: 55.7 µg/m³2025-10-16: 63.1 µg/m³2025-10-17: 62.8 µg/m³2025-10-18: 60.6 µg/m³2025-10-19: 70.9 µg/m³2025-10-20: 105.0 µg/m³2025-10-21: 40.9 µg/m³2025-10-22: 29.3 µg/m³2025-10-23: 24.1 µg/m³2025-10-24: 20.2 µg/m³2025-10-25: no data2025-10-26: no data2025-10-27: 31.5 µg/m³2025-10-28: 17.3 µg/m³2025-10-29: 10.5 µg/m³2025-10-30: 2.1 µg/m³2025-10-31: no data2025-11-01: no data2025-11-02: 61.8 µg/m³2025-11-03: no data2025-11-04: no data2025-11-05: no data2025-11-06: 31.5 µg/m³2025-11-07: 26.7 µg/m³2025-11-08: 34.9 µg/m³2025-11-09: no data2025-11-10: no data2025-11-11: no data2025-11-12: no data2025-11-13: no data2025-11-14: 56.8 µg/m³2025-11-15: 53.8 µg/m³2025-11-16: 45.4 µg/m³2025-11-17: 53.2 µg/m³2025-11-18: no data2025-11-19: no data2025-11-20: no data2025-11-21: 39.0 µg/m³2025-11-22: no data2025-11-23: 50.4 µg/m³2025-11-24: 55.5 µg/m³2025-11-25: no data2025-11-26: 48.5 µg/m³2025-11-27: 53.3 µg/m³2025-11-28: 46.4 µg/m³2025-11-29: no data2025-11-30: no data2025-12-01: no data2025-12-02: 47.1 µg/m³2025-12-03: 58.6 µg/m³2025-12-04: 35.9 µg/m³2025-12-05: 42.0 µg/m³2025-12-06: no data2025-12-07: 57.8 µg/m³2025-12-08: 74.7 µg/m³2025-12-09: 70.5 µg/m³2025-12-10: no data2025-12-11: no data2025-12-12: 71.0 µg/m³2025-12-13: 61.6 µg/m³2025-12-14: no data2025-12-15: 39.2 µg/m³2025-12-16: no data2025-12-17: 64.0 µg/m³2025-12-18: 63.3 µg/m³2025-12-19: 65.0 µg/m³2025-12-20: 62.3 µg/m³2025-12-21: 62.9 µg/m³2025-12-22: 62.3 µg/m³2025-12-23: no data2025-12-24: 70.4 µg/m³2025-12-25: 52.2 µg/m³2025-12-26: 55.8 µg/m³2025-12-27: no data2025-12-28: no data2025-12-29: no data2025-12-30: 44.3 µg/m³2025-12-31: 71.2 µg/m³2026-01-01: 90.1 µg/m³2026-01-02: 74.0 µg/m³2026-01-03: 49.0 µg/m³2026-01-04: 45.8 µg/m³2026-01-05: 71.3 µg/m³2026-01-06: 76.7 µg/m³2026-01-07: 68.6 µg/m³2026-01-08: 82.9 µg/m³2026-01-09: 66.6 µg/m³2026-01-10: 57.6 µg/m³2026-01-11: no data2026-01-12: no data2026-01-13: no data2026-01-14: no data2026-01-15: no data2026-01-16: no data2026-01-17: no data2026-01-18: no data2026-01-19: no data2026-01-20: no data2026-01-21: 56.8 µg/m³2026-01-22: 83.8 µg/m³2026-01-23: 74.9 µg/m³2026-01-24: 71.1 µg/m³2026-01-25: 54.0 µg/m³2026-01-26: no data2026-01-27: 51.8 µg/m³2026-01-28: 52.1 µg/m³2026-01-29: 21.2 µg/m³2026-01-30: 27.6 µg/m³2026-01-31: 33.3 µg/m³2026-02-01: 31.6 µg/m³2026-02-02: 32.7 µg/m³2026-02-03: no data2026-02-04: no data2026-02-05: 32.4 µg/m³2026-02-06: 36.0 µg/m³2026-02-07: 40.2 µg/m³2026-02-08: no data2026-02-09: 43.1 µg/m³2026-02-10: 39.9 µg/m³2026-02-11: 41.5 µg/m³2026-02-12: 38.0 µg/m³2026-02-13: 28.6 µg/m³2026-02-14: 33.5 µg/m³2026-02-15: 33.2 µg/m³2026-02-16: no data2026-02-17: no data2026-02-18: no data2026-02-19: no data2026-02-20: 32.3 µg/m³2026-02-21: 24.9 µg/m³2026-02-22: 28.5 µg/m³2026-02-23: 31.5 µg/m³2026-02-24: 35.3 µg/m³2026-02-25: 33.4 µg/m³2026-02-26: 33.3 µg/m³2026-02-27: 30.8 µg/m³2026-02-28: 28.4 µg/m³2026-03-01: no data2026-03-02: no data2026-03-03: 34.5 µg/m³2026-03-04: 32.4 µg/m³2026-03-05: 36.4 µg/m³2026-03-06: 45.6 µg/m³2026-03-07: 47.5 µg/m³2026-03-08: 49.7 µg/m³2026-03-09: 41.9 µg/m³2026-03-10: no data2026-03-11: no data2026-03-12: 41.4 µg/m³2026-03-13: no data2026-03-14: no data2026-03-15: no data2026-03-16: no data2026-03-17: 33.6 µg/m³2026-03-18: 42.7 µg/m³2026-03-19: no data2026-03-20: 27.3 µg/m³2026-03-21: no data2026-03-22: 11.8 µg/m³2026-03-23: 21.1 µg/m³2026-03-24: no data2026-03-25: no data2026-03-26: no data2026-03-27: no data2026-03-28: no data2026-03-29: 23.4 µg/m³2026-03-30: no data2026-03-31: no data2026-04-01: 38.9 µg/m³2026-04-02: 31.7 µg/m³2026-04-03: 67.7 µg/m³2026-04-04: 35.8 µg/m³2026-04-05: 32.4 µg/m³2026-04-06: 93.7 µg/m³2026-04-07: 24.2 µg/m³2026-04-08: 29.9 µg/m³2026-04-09: 15.6 µg/m³2026-04-10: 25.0 µg/m³2026-04-11: 26.9 µg/m³2026-04-12: 32.8 µg/m³2026-04-13: 33.3 µg/m³2026-04-14: no data2026-04-15: 40.4 µg/m³2026-04-16: no data2026-04-17: 21.7 µg/m³2026-04-18: no data2026-04-19: 19.6 µg/m³2026-04-20: 23.3 µg/m³2026-04-21: 38.4 µg/m³2026-04-22: 31.8 µg/m³2026-04-23: no data2026-04-24: no data2026-04-25: no data2026-04-26: no data2026-04-27: no data2026-04-28: 12.9 µg/m³2026-04-29: 17.8 µg/m³2026-04-30: no data2026-05-01: no data2026-05-02: no data2026-05-03: 6.1 µg/m³2026-05-04: no data2026-05-05: no data2026-05-06: no data2026-05-07: no data2026-05-08: 9.9 µg/m³2026-05-09: 8.6 µg/m³2026-05-10: 9.6 µg/m³2026-05-11: 13.8 µg/m³2026-05-12: 13.9 µg/m³2026-05-13: no data2026-05-14: 7.9 µg/m³2026-05-15: no data2026-05-16: no data2026-05-17: 14.7 µg/m³2026-05-18: 15.0 µg/m³2026-05-19: 12.8 µg/m³2026-05-20: 14.0 µg/m³2026-05-21: 12.8 µg/m³2026-05-22: 8.5 µg/m³2026-05-23: 18.1 µg/m³2026-05-24: 15.5 µg/m³2026-05-25: 15.3 µg/m³2026-05-26: no data2026-05-27: no data2026-05-28: no data2026-05-29: no data2026-05-30: no data2026-05-31: no data2026-06-01: no data2026-06-02: no data2026-06-03: 37.2 µg/m³2026-06-04: no data2026-06-05: no data2026-06-06: no data2026-06-07: no data2026-06-08: 54.9 µg/m³2026-06-09: 36.4 µg/m³2026-06-10: no data2026-06-11: no data2026-06-12: no data2026-06-13: 16.6 µg/m³2026-06-14: 18.9 µg/m³2026-06-15: no data2026-06-16: 45.6 µg/m³2026-06-17: no data2026-06-18: no data2026-06-19: 42.7 µg/m³2026-06-20: no data2026-06-21: 50.0 µg/m³2026-06-22: no data2026-06-23: no data2026-06-24: no data2026-06-25: no data2026-06-26: no data2026-06-27: no data2026-06-28: no data2026-06-29: no data2026-06-30: no data2026-07-01: no data2026-07-02: no data2026-07-03: no data2026-07-04: no data2026-07-05: no data2026-07-06: no data2026-07-07: no data2026-07-08: no data2026-07-09: no data2026-07-10: no data2026-07-11: no data2026-07-12: no data2026-07-13: no data2026-07-14: no data2026-07-15: no data2026-07-16: no data2026-07-17: no data2026-07-18: no data2026-07-19: no data2026-07-20: no data2026-07-21: no data2026-07-22: no data2026-07-23: 45.4 µg/m³2026-07-24: 46.2 µg/m³2026-07-25: 45.7 µg/m³2026-07-26: 45.6 µg/m³2026-07-27: 46.4 µg/m³2026-07-28: 46.3 µg/m³2026-07-29: 46.1 µg/m³2026-07-30: no data2026-07-31: 46.2 µg/m³2026-08-01: 46.2 µg/m³2026-08-02: 46.8 µg/m³2026-08-03: 46.4 µg/m³2026-08-04: no data2026-08-05: 45.4 µg/m³2026-08-06: 46.3 µg/m³2026-08-07: 46.2 µg/m³2026-08-08: 46.3 µg/m³2026-08-09: 46.5 µg/m³2026-08-10: no data2026-08-11: 46.6 µg/m³2026-08-12: 46.0 µg/m³2026-08-13: no data2026-08-14: 46.3 µg/m³2026-08-15: 46.2 µg/m³2026-08-16: 45.8 µg/m³2026-08-17: 46.8 µg/m³2026-08-18: no data2026-08-19: 45.9 µg/m³2026-08-20: 46.6 µg/m³2026-08-21: 46.2 µg/m³2026-08-22: 46.2 µg/m³2026-08-23: no data2026-08-24: 47.0 µg/m³2026-08-25: 46.2 µg/m³2026-08-26: 45.7 µg/m³2026-08-27: no data2026-08-28: no data2026-08-29: no data2026-08-30: 46.2 µg/m³2026-08-31: 46.2 µg/m³2026-09-01: 39.7 µg/m³2026-09-02: 26.9 µg/m³2026-09-03: 29.5 µg/m³2026-09-04: 29.2 µg/m³2026-09-05: no data2026-09-06: no data2026-09-07: no data2026-09-08: no data2026-09-09: no data2026-09-10: no data2026-09-11: no data2026-09-12: no data2026-09-13: no data2026-09-14: no data2026-09-15: no data2026-09-16: no data2026-09-17: no data2026-09-18: 20.0 µg/m³2026-09-19: 28.5 µg/m³2026-09-20: 25.0 µg/m³2026-09-21: 26.9 µg/m³2026-09-22: 23.8 µg/m³2026-09-23: no data2026-09-24: no data2026-09-25: 20.9 µg/m³2026-09-26: 26.2 µg/m³2026-09-27: 35.5 µg/m³2026-09-28: 26.4 µg/m³2026-09-29: no data2026-09-30: no data
Good 0–9.0Moderate 9.1+Unhealthy for sensitive groups 35.5+Unhealthy 55.5+Very unhealthy 125.5+Hazardous 225.5+No data

183 of 200 measured days were over the WHO 24-hour guideline.

Daily world rank

#1#2108NovDecJanFebMarAprMayJunJulAugSep

Rank on each day's board (1 = most polluted city that day).

2026 against 2025, month by month

15Jan 2026: 60.5 µg/m³JanFeb 2026: 33.8 µg/m³FebMar 2025: 68.5 µg/m³Mar 2026: 35.0 µg/m³MarApr 2025: 88.1 µg/m³Apr 2026: 33.0 µg/m³AprMay 2026: 12.3 µg/m³MayJunJulAug 2025: 17.0 µg/m³Aug 2026: 46.3 µg/m³AugSep 2025: 21.5 µg/m³Sep 2026: 27.6 µg/m³SepOct 2025: 40.6 µg/m³OctNov 2025: 46.9 µg/m³NovDec 2025: 58.7 µg/m³Dec

Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 27.3 µg/m³27.320252025: 26.0 µg/m³26.0

Mean PM2.5 for 24 Sept to 30 Sept in each year. Dashed line: WHO 24-hour guideline.

Monitors

StationOperatorType
Chitragupta Nagar, Siwan - BSPCBGODL-IndiaBihar State Pollution Control BoardReference

The city's value is the median of its reference monitors each hour; low-cost sensors are listed but not counted when reference monitors exist. Data via OpenAQ; licences as listed. How we rank. Embed this on your site.

Other cities in India

Dera Māndi 68.4Jīnd 65.7Gurugram 61.6Yamuna Nagar 60.3Jammu 54.6Noida 51.8Kaithal 51.7Bhiwadi 50.6Dādri 48.2Dhāruhera 47.8Jalandhar 45.4Faridabad 42.6

30-day averages, µg/m³. All of India →

Updated 2026-10-01 06:07 UTC. Values are PM2.5 in µg/m³ (fine particles), the median of each city's monitors.