Delhi’s air quality improved significantly and values of harmful prominent pollutant were recorded under “moderate” category. This was the first time in this winter season post Diwali when concentration of Particulate Matter (PM) 10 and PM 2.5 were recorded 143 and 95 microgram per cubic on the National Ambient Air Quality Index (NAAQI).
With this, SAFAR, a unit of Ministry of Earth Sciences (MoES ) marked Delhi’s map with ‘orange’, this further means that air quality is less noxious.
Citing moderate rainfall and wind speed, System of Air Quality and Weather Forecast and Research (SAFAR) said, “The last night rainfall along with moderate wind speed were sufficient enough to wash away air pollutants significantly and improved the AQI to poor level,” “It has improved further in day time due to wind speed. It may be noted that this respite is not expected last longer as relative humidity is very high and temperature is likely to cool,” Quoted SAFAR’s statement.
SAFAR, however, in its forecast also mentioned that respite is expected not to last longer as relative humidity is very high and temperature is likely to cool. “Both factors are unfavorable and if winds slow down, pollution may start to build -up faster, and thus Average Air quality Index (AQI) may push very poor level by weekend.
The AQI on Monday was 412, on Tuesday 415 and 413 on Wednesday morning.
An AQI between 100 to 200 comes under moderate category, 201 and 300 is considered ‘poor’, 301 and 400 ‘very poor’ and 401 and 500 ‘severe’.
Neighbouring Ghaziabad and Faridabad recorded ‘poor’ air quality, while Gurgaon and Noida recorded ‘moderate’ air quality, the CPCB data showed.
According to the Indian Institute of Tropical Meteorology, the maximum ventilation index is likely to be 3,500 sqm/second on Thursday and 7,000 sqm/second on Friday.
A ventilation index lower than 6,000 sqm/second with average wind speed less than 10 kmph are unfavourable for dispersion of pollutants.