First severe smog hits Delhi, national capital could witness season's longest since 2017: Report

This year could be the worst smog episode for Delhi and its neighbouring areas, warn the green think-tank Centre for Science and Environment (CSE). According to the green think-tank, smog is expected to last for another two days in the Delhi-NCR regions.

This means that the first severe smog episode in Delhi could be the longest in four years. According to Anumita Roychowdhury, Executive Director, CSE research and advocacy, the season's first smog episode has been triggered by the combined effect of unfavourable weather conditions, stubble burning and firecrackers.

On the other hand, CSE data says the average daily contribution of smoke from farm fires has been the lowest in the last four years during the time period from the middle of October to November 8. The peak contribution of smoke to Delhi's PM level was recorded on November 7 when it hit 48%. The green think-tank says this year's first smog episode has already lasted six days which matches that of 2018 and 2020. 

However, this could further increase if conditions do not improve and may even overtake the 2019 record of eight days. The average intensity of the smog this year so far is 329 micrograms per cubic metre per day. This is lower by 7% than that of 2020 smog and by 3% than that of 2019 smog. However, it is more intense than that of 2018 smog by about 9%.

The green think tank has blamed the lack of pollution control measures in the city for a longer duration of smog episodes in Delhi despite relatively windier local conditions. The analysis has been done on the basis of real-time data available from the current working air quality monitoring stations in Delhi-NCR and the larger Indo-Gangetic Plain.

(With Agency Inputs)