CAQM invokes GRAP Stage-IV across NCR as Delhi's AQI crosses 400
The CAQM Sub-Committee on GRAP invoked Stage-IV ('Severe+' air quality) across the entire NCR on 16 December 2024 after Delhi's average AQI reached 401.
Summary
The Commission for Air Quality Management (CAQM) Sub-Committee on the Graded Response Action Plan (GRAP) invoked Stage-IV ('Severe+' air quality) of the GRAP schedule, as revised and issued on 13 December 2024, across the entire NCR with immediate effect on the night of 16 December 2024. Delhi's average AQI was 399 at 9 PM and 401 at 10 PM, breaching the 400 mark amid a drastic reduction in mixing layer height and calm wind conditions. The step followed the Supreme Court's directions of 5 December 2024 in M.C. Mehta vs Union of India that Stage-III must be implemented if the AQI goes above 350 and Stage-IV reintroduced if it crosses 400. Stage-III had been invoked earlier the same day.
Key facts
- Invoked
- Night of 16 December 2024, entire NCR
- Trigger
- Delhi average AQI 399 at 9 PM; 401 at 10 PM
- Schedule
- GRAP as revised and issued on 13 December 2024
- SC direction
- M.C. Mehta vs Union of India, 5 December 2024
- SC thresholds
- Stage-III above AQI 350; Stage-IV above AQI 400
- Earlier
- Stage-III invoked earlier on 16 December 2024
Practice MCQs 2 questions
What was Delhi's average AQI at 10 PM on 16 December 2024, when the CAQM invoked GRAP Stage-IV across the NCR?
Show answer
Correct answer: C — 401
PIB (Environment): the Sub-Committee noted that the AQI was 399 at 9 PM and was recorded as 401 at 10 PM, breaching the 400 mark, and invoked Stage-IV.
As per the Supreme Court's directions of 5 December 2024 in M.C. Mehta vs Union of India, GRAP Stage-III measures must be implemented immediately if Delhi's AQI goes above:
Show answer
Correct answer: B — 350
PIB (Environment): the Supreme Court directed that if the AQI goes above 350, Stage-III measures will have to be immediately implemented, and if it crosses 400, Stage-IV measures will have to be reintroduced.