Uttarakhand: average air quality index over the 7 days to 12 September 2026 was 53, above the 3-year median of 41 for the same week (+28%).

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.

The number being averaged changed (about 2 now against 3 in earlier years), so part of this reflects which places are measured. Same week in earlier years: 2025 41, 2024 41, 2023 71. Daily values are compared as 7-day means because a single day mostly reflects weather.

Full history of average air quality index in Uttarakhand