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News: Yesterday, air quality in Delhi inched towards the ‘very poor’ category, with Air Quality Index (AQI) being recorded as 283. The Commission on Air Quality Management (CAQM) has already invoked Stage 1 of GRAP after AQI dropped significantly in Delhi post- Dussehra celebrations.
1. Air Quality Index (AQI): It is a tool used by the government agencies to track air pollution levels and communicate risks to the public.
2. The National Air Quality Index is released by the Central Pollution Control Board.
3. There are 6 AQI categories, namely Good (0-50), Satisfactory (51-100), Moderately Polluted (101-200), Poor (201-300), Very Poor (301-400), Severe (401-500).
4. Pollutants measured by AQI include Nitrogen Dioxide, PM 10, PM 2.5, Ozone etc.
5. Graded Response Action Plan (GRAP): It is an emergency response mechanism that is implemented to prevent further deterioration of air quality once it reaches a certain threshold in the Delhi-NCR region.
6. The 4 stages of GRAP system are: A) Stage 1: Poor AQI 201-300 B) Stage 2: Very Poor AQI 301-400 C) Stage 3: Severe AQI 401-450 D) Stage 4: Severe Plus AQI >450.



