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New Delhi on Friday witnessed a surge in air quality from a clean to moderate category after reporting clean air for several weeks amid COVID-19.

The overall air quality of Delhi started to decline once again after the Unlock phase has begun in the city.

New Delhi has witnessed a never before cleaner air quality during the lockdown from March to June but the city is shedding the air quality once the Unlock started in June.

The overall air quality of Delhi remained in the moderate category for the second consecutive day on Friday according to an update by System of Air Quality and Weather Forecasting and Research.

According to the Central Pollution Control Board, several areas in the national capital including Alipur, Mathura Road, IGI Airport terminal 3 road, and Dwaraka recorded the air quality in the moderate category which showed an air quality index of 133, 153, 133, and 173 respectively.

Meanwhile, many areas in Delhi have recorded air quality in a satisfactory category. Places like Aanand Vihar, ITO-Delhi, Lodhi road, Mandir Marg, Pusa-IMD, have recorded the air quality in the levels of 90, 90, 98, 79, and 79 respectively.

According to the CPCB, the air quality index between 50 to 100 is considered to be satisfactory or very good and 101 to 200 is considered moderate air quality, and anything above 200 and under 300 falls under the category of poor.

Moreover, 300 to 400 is considered very poor and the levels between 401 to 500 air quality comes under the hazardous category.

The nationwide lockdown which has run for several months has significantly reduced the emissions of various pollutants and the distribution of their concentration not only on the surface but also vertically up in the atmosphere.

This is the reason why there has been a huge reduction in the accumulated emission mass.

However, when the unlock period started, the scattered monsoon rains that have originated in the Bay of Bengal and moved northwestward has continued to wash away particulate pollutants in Delhi and the surrounding north Indian regions not allowing any accumulation of pollution in the city.

There are indications that unlocking the country has not led to the 100 percent pre-COVID levels in the air quality due to the reduced activities.

Moreover, the wind speed mainly from the south easterly to eastern direction has led to flush out the pollutants that have been accumulated even in the present time.

The easterly winds are also helping in blocking out the relatively dusty air from the region. The unusually high-speed winds in Delhi recently have cleaned the Delhi pollution further.

Noida and Gurugram are the first cities to have reported declining air quality after the lockdown has lifted as these are the busiest areas.

By Gayatri Yellayi