Delhi-NCR AQI turns Severe; CAQM moves GRAP Stage 3 to Stage 4
Why in the news
Air quality in Delhi-NCR deteriorated sharply on Saturday, 13 December 2025, pushing the Commission for Air Quality Management (CAQM) to tighten curbs twice in a single day.
Key facts
- AQI: crossed 400 in the afternoon, entering the Severe category; 431 at 4 pm and 441 at 6 pm.
- GRAP Stage 3: invoked first by CAQM when the index crossed 400.
- GRAP Stage 4: imposed by the evening as the index kept rising.
- Causes: weak Western Disturbance, low wind speeds, calm conditions and higher moisture trapping pollutants.
- Impact: schools may shift some classes online and offices were advised to allow 50% remote work.
| Time on 13 Dec | AQI / action |
|---|---|
| Afternoon | AQI crosses 400; GRAP Stage 3 |
| 4 pm | AQI 431 |
| 6 pm | AQI 441; GRAP Stage 4 |
About CAQM and GRAP
- CAQM is the statutory body that implements the Graded Response Action Plan (GRAP) in the National Capital Region.
- GRAP applies stronger curbs in stages as air quality worsens.
- Stage 4 curbs include a ban on non-essential trucks (except those carrying essential goods or using cleaner fuels), a bar on older diesel vehicles and a halt to construction.
Exam angle
- Know that CAQM, not the Delhi government alone, imposes GRAP stages.
- Remember the Severe threshold used in the report: AQI above 400.
- Link meteorological causes such as a Western Disturbance to pollution episodes.