Delhi’s winter air quality has shown no consistent improvement in the four years since the revision of the Graded Response Action Plan (GRAP) in 2022, with the city experiencing high pollution levels despite frequent imposition of stringent curbs, according to an analysis by the Centre for Research on Energy and Clean Air (CREA).

The city’s mean Air Quality Index (AQI) rose from 280 in the winter of 2022-23 to 304 in 2023-24, declined to 285 in 2024-25 and increased again to 295 in 2025-26, said Manoj Kumar, an analyst at CREA.

The median AQI also fluctuated, rising from 294 in 2022-23 to 324 in 2023-24, falling to 289 in 2024-25 and climbing to 305 last winter.

The findings indicate that the capital’s winter air quality has not followed a sustained downward trend since the revised GRAP framework was introduced, with both mean and median AQI levels in 2025-26 higher than those recorded in 2022-23.