Delhi pollution out of ‘severe’ zone as air quality improves, expect better days ahead
The Central Pollution Control Board data shows that the Air Quality Index which had shot up to 408 on Tuesday, had come down to 380 around 8am on Wednesday. The visibility, both in the city and at the airport, had also improved.delhi Updated: Jan 03, 2018 10:13 IST
Here’s some good news to start your day with. Air quality in the national capital, which had breached ‘severe’ levels on Tuesday, improved marginally on Wednesday morning, to return to ‘very poor’.
Both the visibility and pollution levels are expected to improve further over the next few days, experts said.
The minimum temperature on Wednesday morning was at 7.4 degrees Celsius. On Monday the mercury had dropped to 5.7 degrees Celsius — the season’s lowest. On Tuesday, though the minimum had improved to 8.4 degree Celsius, the maximum was at 17.7 degree Celsius — the lowest maximum of the season so far.
The Central Pollution Control Board data shows that the Air Quality Index — a measure of pollutants in the air — which had shot up to 408 on Tuesday, had come down to 380 around 8am on Wednesday. On the New Year day it was 400. On a scale of 0-500, an AQI value between 300 and 400 is considered to be ‘very poor’. A value beyond 400 is termed as ‘severe’ level of pollution.
The visibility, both in the city and at the airport, had also improved, said officials at the Regional Weather Forecasting Centre (RWFC). “The visibility, that had dropped to around 300m around 8.30am on Tuesday at Palam, had improved to 500m around the same time on Wednesday. At Safdarjung too, the visibility improved from 300m on Tuesday to 800m on Wednesday,” a senior official of the RWFC said.
The weatherman attributed this primarily to the increase in wind velocity. Moisture levels haven’t changed much since Tuesday and the maximum relative humidity is still above 90 per cent.
“The wind speed has almost doubled over the last 24 hours. While the wind was blowing with a speed of around 4km/hr on Tuesday morning, the velocity increased to around 8km/hr on Wednesday morning,” the official said.
As the wind picked up speed the concentration of particulate matter — primary pollutants in Delhi’s air — also dropped, though marginally.
While PM10 levels have dropped from 450ug/m3 at 11pm on Tuesday to around 448ug/m3 at 9am on Wednesday, the concentration of PM2.5 has also dropped from 266ug/m3 to around 262ug/m3 during the same period.
“Strong winds from the north and north-west are vital for improving Delhi’s air quality. They help to flush out the pollutants,” said D Saha, head of the air quality laboratory at CPCB.
India’s official pollution forecasting system SAFAR has said that the air quality is likely to improve further as level of particulate matter is expected to decline.
First Published: Jan 03, 2018 10:07 IST