New Delhi: The city’s AQI stood at 401 in the severe range on Monday night, a massive deterioration from the average of 294 a day before.
After the AQI entered the severe range on Monday night, CAQM imposed stage IV restriction under GRAP in NCR with immediate effect.
Anti-pollution experts said meteorological conditions such as calm winds, low temperatures and an increase in moisture facilitated the trapping of pollutants.
“Delhi had seen strong north-westerly winds recently, which aided in the dispersion of pollutants,” Mahesh Palawat, the vice-president of Skymet Meteorology, said. “However, as a western disturbance has impacted north-west India, the wind speed has significantly reduced. This has caused the accumulation of pollutants in the air. Besides, an increase in moisture caused the trapping of pollutants. A calm wind is expected on Tuesday too,” he said. After the influence of the western disturbance ebbs, the wind speed could rise from Wednesday, he added.
On Monday evening, the AQI was 379, already in the very poor range, at 4 pm.
As the winds slowed, the AQI rose rapidly. A haze hung over the city on Monday. Central Pollution Control Board’s data shows that the AQI was 351 at 9am on Monday, spiked to near severe at 398 at 8pm, and rose further to 401 at 10pm.
As Delhi mostly saw good wind speed in the first fortnight of Dec, the average AQI from Dec 1 to 15 was 238.
This was the lowest AQI reported for this period since CPCB started measuring AQI in 2015.
“The average AQI of Delhi has crossed 350 today and is showing an increasing trend owing to extremely calm wind conditions and the build-up of an inversion layer, also adversely affecting the vertical mixing height,” CAQM in a statement earlier on Monday.
Anand Vihar was the most polluted station on Monday with a reading of 437 at 4pm, followed by Punjabi Bagh at 431.
According to the Air Quality Early Warning System for Delhi, which is the forecasting body under the Union ministry of earth sciences, the air quality is likely to be severe on Tuesday too.
