Delhi air ‘severe’ for the sixth time in 19 days

Delhi’s air quality slipped into the “severe” zone on Tuesday, for the sixth time since New Year, the Central Pollution Control Board (CPCB) recordings show. In comparison, Delhi had only two “ severe” air days for the month of January in 2020.

Records on Tuesday showed that the overall air quality index (AQI) of the city was 404, in the ”severe” category. This was a deterioration from Monday’s AQI of 372, in the “very poor” category. On a scale of 0 to 500, a reading between 300 and 400 is considered “very poor”, while a reading between 400 and 500 is considered “severe”.

This was the sixth time in the 19 days of January that the AQI has deteriorated to the “severe” level. In 2020, the month of January had only two such days.

Scientists from the India Meteorological Department (IMD) said this deterioration in air quality was “unforeseen” and was caused mainly by the dense fog that enveloped the city in the early hours of Tuesday.

VK Soni, head of IMD’s environment monitoring and research centre, said after the fog layer lifted, wind speed picked up and dispersion of pollutants started. The impact of this ventilation would be seen on Wednesday, when the average AQI is expected to climb down to the ”very poor” zone.

“The dense fog that we saw in the morning was not something that we had anticipated -- it had drifted in from neighbouring states. However, around 10am Tuesday, Delhi started getting winds of considerably high speed from the north-western side. The wind speed during the day was between 12kmph and 15kmph,” Soni said.

He said the air quality will improve over the next two days but will remain in the ”very poor” zone. From January 21, a western disturbance passing over the western Himalayas will also speed up winds over Delhi and thereby bring down the pollution levels further.

From Wednesday, the IMD has forecasted moderate fog over Delhi. On Tuesday, the minimum temperature at the Safdarjung weather station, which is considered the official marker for the city, was 6.9 degrees Celsius. The maximum temperature was 20.4 degrees Celsius, one degree above the season’s normal.

Meanwhile, as the pollution levels spiked in the national capital, the pollution control boards of Delhi, Haryana, Rajasthan and Uttar Pradesh submitted inspection reports of a drive against construction and demolition (C&D) waste in Delhi-NCR, as directed by the Commission for Air Quality Management (CAQM).

The CAQM had directed the CPCB, and the state pollution control boards of Delhi, Haryana, Rajasthan and Uttar Pradesh to constitute special teams and inspect construction sites in Delhi-NCR. In their respective reports of inspections, conducted between December 31 and January 15, 1,600 sites were penalised for not abiding by the C&D waste management rules.

“Between December 31 and January 15, agencies constituted 174 teams, and an amount of nearly ₹51 lakh was collected as environment compensation charges from defaulting parties, besides issuing orders for stoppage of work at 27 locations,” a statement from the CPCB said.