The Graded Response Action Plan (GRAP) is a scheme and a set of emergency measures designed to prevent the further deterioration of air quality once it reaches a certain threshold in the National Capital Region (NCR). The mechanism was first notified in January 2017 by the Ministry of Environment, Forest and Climate Change (MoEFCC) to address the problem of severe, recurring air pollution through a structured, pre-emptive approach. Its foundation was a plan submitted by the Central Pollution Control Board (CPCB) in November 2016.
The mechanism works by linking four distinct stages of escalating restrictions to specific Air Quality Index (AQI) categories. Stage 1 is activated when the AQI is in the 'poor' category (201 to 300), while Stage 2 is triggered three days ahead of the AQI reaching the 'very poor' category (301 to 400). The most stringent measures, including potential bans on non-essential construction and the odd-even system for vehicles, are reserved for Stage 4, which is activated when the AQI is projected to cross the 'severe +' category (above 450). A key provision is that measures imposed under a previous stage remain in force even after a subsequent stage is activated.
GRAP connects directly to the Commission for Air Quality Management (CAQM), which has been responsible for its implementation since 2021, replacing the previously dissolved Environment Pollution (Prevention and Control) Authority for the NCR. The CAQM relies on air quality and meteorological forecasts provided by the Indian Institute of Tropical Meteorology (IITM) and the India Meteorological Department (IMD) to pre-emptively enforce the stages. The GRAP was recently revised by the CAQM earlier in 2022, though the core principle of a graded, pre-emptive response based on AQI thresholds remains the same.