India, Dec. 14 -- Authorities in Delhi and the National Capital Region (Delhi-NCR) invoked the Graded Response Action Plan (GRAP)-IV on December 13, 2025, as air quality worsened to hazardous levels.

The GRAP framework was approved by the Supreme Court in 2016, and its implementation has since been overseen by the Commission for Air Quality Management. Governments in Delhi-NCR must act in accordance with the GRAP mechanism as air pollution levels rise through various stages.

There are four stages in GRAP, each linked to the Air Quality Index (AQI) at the time.

When the AQI is 201-300 or the air quality is categorised as 'poor', GRAP-I or the first stage of the framework kicks in. The second stage is invoked when the air quality becomes...