Outside the usual range1 October 2026Environment
West Bengal: average air quality index over the 7 days to 1 October 2026 was 69, above the 5-year median of 56 for the same week (+22%).
What happened
- 7-day mean to 1 October 2026
- 69
- That day alone: 93
- 5-year median, same week
- 56
- Change
- +12
- Change, per cent
- +22%
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 a deterioration.
Historical context
Same week in earlier years: 2025 56, 2024 56, 2023 54, 2022 85, 2021 56. 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 |
|---|---|---|---|
| 1 October 2026 | 93 | CPCB National Air Quality Index bulletin, 1 October 2026 (247 cities) | AQI bulletin p.1–11, Index Value column: mean of 7 city rows placed in West Bengal — Asansol (p.1), Barrackpore (p.2), Durgapur (p.4), Haldia (p.5), Howrah (p.6), Kolkata (p.7), Siliguri (p.11) |
| 30 September 2026 | 103 | CPCB National Air Quality Index bulletin, 30 September 2026 (255 cities) | AQI bulletin p.1–8, Index Value column: mean of 6 city rows placed in West Bengal — Asansol (p.1), Barrackpore (p.2), Durgapur (p.5), Haldia (p.6), Howrah (p.6), Kolkata (p.8) |
| 29 September 2026 | 84 | CPCB National Air Quality Index bulletin, 29 September 2026 (252 cities) | AQI bulletin p.1–11, Index Value column: mean of 7 city rows placed in West Bengal — Asansol (p.1), Barrackpore (p.2), Durgapur (p.5), Haldia (p.6), Howrah (p.6), Kolkata (p.8), Siliguri (p.11) |
| 28 September 2026 | 76 | CPCB National Air Quality Index bulletin, 28 September 2026 (238 cities) | AQI bulletin p.1–7, Index Value column: mean of 5 city rows placed in West Bengal — Asansol (p.1), Durgapur (p.4), Haldia (p.5), Howrah (p.5), Kolkata (p.7) |
| 27 September 2026 | 50 | CPCB National Air Quality Index bulletin, 27 September 2026 (235 cities) |
Source and method
- Release
- CPCB National Air Quality Index bulletin, 1 October 2026 (247 cities)Archived fileOriginal URLFirst seen 3 Oct 2026
More signals for average air quality index in West Bengal
- West Bengal: average air quality index over the 7 days to 3 October 2026 was 87, above the 5-year median of 53 for the same week (+63%).
- West Bengal: average air quality index of 106 on 3 October 2026 is the highest since 6 March 2026.
- West Bengal: average air quality index of 103 on 30 September 2026 is the highest since 6 March 2026.
- West Bengal: average air quality index over the 7 days to 26 September 2026 was 44, below the 5-year median of 59 for the same week (−25%).
- West Bengal: average air quality index of 37 on 25 September 2026 is the lowest since 30 October 2025.
- West Bengal: average air quality index of 38 on 24 September 2026 is the lowest since 30 October 2025.
Cite this
According to the India Health Observatory, West Bengal: average air quality index over the 7 days to 1 October 2026 was 69, above the 5-year median of 56 for the same week (+22%). Source: Central Pollution Control Board, Ministry of Environment, Forest and Climate Change, CPCB National Air Quality Index bulletin, 1 October 2026 (247 cities). https://indiahealthobservatory.com/signals/air-quality-index--west-bengal--2026-10-01--baseline_breach
See also West Bengal and 93 AQI in context.