NEW DELHI: The city’s air quality turned ‘very poor’ on Wednesday, a day before Diwali, worsening from ‘poor’ a day earlier due to calm winds and high locally generated pollution, with emissions from transport the leading contributor.
As per IITM’s air quality early warning system under the earth sciences ministry, the city’s air is likely to remain very poor on Diwali day as well as Nov 1. But it may turn ‘severe’ on these days if additional emissions from firecrackers and stubble or waste fires add to the city’s pollution.
The day’s average Air Quality Index (AQI), on a scale of 0 to 500, was 307 at 4pm, with two stations (Anand Vihar and Mundka) reporting severe air quality. It added that winds may vary from four to 20 kmph on Diwali with the possibility of mist in the morning and a mainly clear sky. The wind speed will drop a day after Diwali.
Anand Vihar had the worst air quality in the city on Wednesday with an AQI of 407, followed by Mundka at 401. The city’s AQI, however, kept worsening towards late evening due to calm winds.
“The air quality may reach the severe category on Oct 31 and Nov 01 in case of additional emissions from firecrackers and stubble/waste fires. Outlook for the subsequent six days: Very poor to severe,” stated IITM’s air quality early warning system.
A day earlier (Tuesday), the city’s average AQI was 268, in the poor zone. An AQI of 201 to 300 is considered poor, 301 to 400 very poor, while a value between 401 and 500 is considered severe.
As per IITM’s Decision Support System (DSS), while the share of stubble burning in the city’s PM2.5 levels increased slightly to 3.4% on Tuesday, against 1.8% on Monday, it was still low and local sources had more impact on the city’s air quality. The DSS shares display the actual share of stubble burning for the previous day.
On Wednesday, transport remained the major source of pollution in the city, contributing 16.2% of all pollution, followed by pollution coming from Gautam Budh Nagar (7.4%), Faridabad (7.3%), Ghaziabad (4.3%), residential emissions (4.2%), industries (3.7%), Gurgaon (3.5%), and construction sector (2.1%).
According to CPCB, PM2.5 levels on Wednesday oscillated between 104 to 166.6 micrograms per cubic metre – rising as the day proceeded, while the national safe standard for PM2.5 is 60 units, and the WHO has set the limit at 15 units for 24 hours.