The air quality of Delhi and Gurugram was in the “poor” category and Noida’s was in the “very poor” category, as per the Central Pollution Control Board (CPCB). The air quality of the national capital is expected to deteriorate to the “very poor” category on Thursday and “severe” on Friday.
“The AQI is forecast to deteriorate to the high-end of the ‘very poor’ category by December 31. The AQI may touch the ‘severe’ category for a short period on New Year’s Eve. ‘Very poor’ to ‘severe’ air quality is forecast on January 1. Calm wind-low ventilated condition is likely to extend for the first few days of the New Year,” said a statement by the government-run monitoring agency SAFAR (System of Air Quality and Weather Forecasting and Research). Stubble burning
The effect of stubble burning on the city’s air quality remained low on Wednesday.
But apart from pollutants, two meteorological factors strongly impact the air quality.
The “mixing layer height”, which is the height from the ground level up to which pollutants can be dispersed, remained “moderate”. This led to lesser accumulation of pollutants near the surface.
Also, the speed of surface-level winds was “moderate”, which aided in lesser accumulation of pollutants. Faster surface winds help in the dispersion of pollutants. The speed was predicted to pick up speed.
“Due to the cold dry north-westerly winds and a fall in minimum temperature is likely in the region and a gradual decrease of surface wind speed is forecast. Very calm surface winds along with low boundary layer height will lead to extremely low ventilation conditions on December 31 and January 1,” SAFAR said.
The AQI of Delhi was 290, as per CPCB’s 4 p.m. bulletin, which is an average of the past 24 hours. The values for Gurugram and Noida were 227 and 302 respectively.
An AQI between 0 and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.
