Delhi’s battle with toxic air has intensified, with the air quality remaining in the “severe” category for the second consecutive day. A thick blanket of smog hangs over the city, trapping pollutants close to the surface due to dipping temperatures and low wind speeds.
The 24-hour rolling average Air Quality Index (AQI) was recorded at 413 at 8:00 am, a marginal drop from the 4:00 pm reading of 428 on Tuesday, which is when the Central Pollution Control Board (CPCB) releases its daily national bulletin.
Worst Air Since Last Year; GRAP-3 Implemented
The pollution level recorded on Tuesday marked the worst AQI for Delhi since December 19 last year, when the index hit 451.
This severe deterioration immediately triggered action from the Commission for Air Quality Management (CAQM) in NCR and Adjoining Areas, which announced the implementation of measures under Stage-3 of the Graded Response Action Plan (GRAP).
Atmospheric Inversion Traps Smog
Experts attribute the sharp decline in air quality primarily to two meteorological factors: dipping temperatures and a drop in wind speed, which together lead to a phenomenon known as inversion.
- Inversion Explained: In an inversion, a layer of warm air sits above cooler air near the ground. This warm layer acts like a lid, effectively trapping the cool air and, critically, the pollution close to the surface.
- Result: This prevents pollutants from dispersing, leading to the visible haze or smog and the alarming spike in AQI.
Forecast and GRAP-3 Restrictions
There is a slight hope for relief, as forecasts indicate that winds are likely to marginally pick up on Wednesday. Mahesh Palawat, Vice President of private forecaster Skymet Weather, noted that winds began to strengthen post-noon on Tuesday, reaching up to 12 km per hour, and are expected to stay consistent, potentially reaching 20 km per hour during the day on Wednesday.
“So there is a chance of marginal improvement in the air quality,” Palawat said, adding that the AQI is expected to improve to the “very poor” category later today.
Meanwhile, the following restrictions remain in place under GRAP-3 across Delhi, Gurugram, Faridabad, Ghaziabad, and Gautam Budh Nagar:
- Construction Ban: Private or non-essential construction activities are strictly prohibited.
- Vehicle Restrictions: Restrictions are enforced on private BS-3 petrol and BS-4 diesel four-wheelers.
- Schools: Schools, until Class 5, are required to operate in a “hybrid” mode to protect young children from the toxic air.
Data from CPCB’s Sameer app confirmed the severity of the crisis, showing that 32 of the 39 active air quality monitoring stations in the city were recording air quality in the ‘severe’ category on Tuesday.