West Bengal: highest city air quality index over the 7 days to 18 September 2026 was 76, above the 5-year median of 63 for the same week (+21%).

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 highest city air quality index, lower is better. This movement is therefore assessed as a deterioration.

Same week in earlier years: 2025 62, 2024 89, 2023 63, 2022 89, 2021 61. Daily values are compared as 7-day means because a single day mostly reflects weather.

Full history of highest city air quality index in West Bengal