Outside the usual range12 September 2026Environment
Bihar: average air quality index over the 7 days to 12 September 2026 was 66, below the 5-year median of 82 for the same week (−20%).
What happened
- 7-day mean to 12 September 2026
- 66
- That day alone: 56
- 5-year median, same week
- 82
- Change
- −16
- Change, per cent
- −20%
Why it matters
Daily figures mostly reflect the weather, so the observatory compares the mean of the last seven days with the same week in up to five earlier years. A breach means this week sits well outside what those years would lead you to expect, and by at least 15%. It is reported when an unusual run begins and for the latest day while it lasts, not every day.
For average air quality index, lower is better. This movement is therefore assessed as an improvement.
Historical context
Same week in earlier years: 2025 82, 2024 74, 2023 82, 2022 84, 2021 66. Daily values are compared as 7-day means because a single day mostly reflects weather.
The underlying data
| Period | Value | Release | Where in the document |
|---|---|---|---|
| 12 September 2026 | 56 | CPCB National Air Quality Index bulletin, 12 September 2026 (245 cities) | AQI bulletin p.1–11, Index Value column: mean of 17 city rows placed in Bihar — Araria (p.1), Arrah (p.1), Begusarai (p.2), Bhagalpur (p.2), Gaya (p.5), Hajipur (p.5), Katihar (p.7), Kishanganj (p.7), Manguraha (p.8), Motihari (p.8), Munger (p.8), Muzaffarpur (p.9), Patna (p.10), Purnia (p.10), Rajgir (p.10), Saharsa (p.11), Sasaram (p.11) |
| 11 September 2026 | 58 | CPCB National Air Quality Index bulletin, 11 September 2026 (242 cities) | AQI bulletin p.1–11, Index Value column: mean of 16 city rows placed in Bihar — Araria (p.1), Arrah (p.1), Begusarai (p.2), Bettiah (p.2), Bhagalpur (p.2), Chhapra (p.4), Gaya (p.5), Hajipur (p.5), Katihar (p.7), Kishanganj (p.7), Motihari (p.8), Muzaffarpur (p.9), Patna (p.10), Purnia (p.10), Rajgir (p.10), Saharsa (p.11) |
| 10 September 2026 | 63 | CPCB National Air Quality Index bulletin, 10 September 2026 (243 cities) | AQI bulletin p.1–11, Index Value column: mean of 19 city rows placed in Bihar — Araria (p.1), Arrah (p.1), Begusarai (p.2), Bettiah (p.2), Bhagalpur (p.2), Bihar sharif (p.3), Chhapra (p.4), Gaya (p.5), Hajipur (p.5), Katihar (p.7), Kishanganj (p.7), Manguraha (p.8), Motihari (p.8), Muzaffarpur (p.9), Patna (p.10), Purnia (p.10), Rajgir (p.10), Saharsa (p.11), Sasaram (p.11) |
| 9 September 2026 | 79 | CPCB National Air Quality Index bulletin, 9 September 2026 (252 cities) | AQI bulletin p.1–11, Index Value column: mean of 19 city rows placed in Bihar — Araria (p.1), Arrah (p.1), Begusarai (p.2), Bettiah (p.2), Bhagalpur (p.2), Bihar sharif (p.3), Chhapra (p.4), Gaya (p.5), Hajipur (p.5), Katihar (p.7), Kishanganj (p.7), Munger (p.9), Muzaffarpur (p.9), Patna (p.10), Purnia (p.10), Rajgir (p.11), Saharsa (p.11), Samastipur (p.11), Sasaram (p.11) |
Source and method
- Release
- CPCB National Air Quality Index bulletin, 12 September 2026 (245 cities)Archived fileOriginal URLFirst seen 3 Oct 2026
More signals for average air quality index in Bihar
Cite this
According to the India Health Observatory, Bihar: average air quality index over the 7 days to 12 September 2026 was 66, below the 5-year median of 82 for the same week (−20%). Source: Central Pollution Control Board, Ministry of Environment, Forest and Climate Change, CPCB National Air Quality Index bulletin, 12 September 2026 (245 cities). https://indiahealthobservatory.com/signals/air-quality-index--bihar--2026-09-12--baseline_breach
See also Bihar and 56 AQI in context.