Delhi's air quality reaches 'severe' levels, ITO's AQI at 455
What's the story
Delhi woke up to a day of toxic air on Friday, with several areas slipping into the "severe" category. The Central Pollution Control Board (CPCB) recorded the worst air quality at ITO, where the Air Quality Index (AQI) reached 455 at 5:55am. The area around All India Institute of Medical Sciences (AIIMS) followed closely with an AQI of 418 at 7:20am.
Pollution levels
Akshardham also records severe AQI readings
The area around the Akshardham temple also recorded a "severe" AQI of 414 at 5:25am.
The Rajokri border area wasn't far behind, with an AQI of 402 at 6:50am.
In stark contrast, Dhaula Kuan recorded a "moderate" AQI of 128 at 6:30am.
Pollution persistence
GRAP invoked on November 6
The deterioration in Delhi's air quality comes despite measures under the Graded Response Action Plan (GRAP).
Stage III of GRAP was invoked across Delhi-NCR on November 6 after AQI readings reached 382. Forecasts indicated further deterioration.
PM2.5 concentrations more than doubled within a day to 244 micrograms per cubic meter by Thursday evening.
Dispersal challenges
Weak surface winds, humidity trap pollutants
Weak surface winds and high humidity have made it difficult for pollutants to disperse.
The mixing layer, which determines how much air is available to disperse pollutants, shrank to approximately 400 meters on Thursday afternoon from 1,400 meters two days earlier.
North-westerly winds have also resumed carrying smoke from agricultural fires in Punjab and Haryana toward Delhi.
Pollution control
GRAP measures in place
Under the revised GRAP framework, AQI readings of 401-450 fall under the "severe" category while those above 450 are classified as "severe plus."
The measures include curbs on construction and demolition activities, restrictions on polluting vehicles, among other emergency pollution-control measures.
The situation remains alarming, with Dwarka Expressway recording an AQI of 369 (Very Poor) and Jawaharlal Nehru Stadium area registering a reading of 374.