New Delhi: Air pollution levels in Delhi spiked many times over the safe limits on Diwali night, albeit the overall 24-hour average of air quality index released Monday settled in the ‘very poor’ category at 368. This is the worst recorded AQI in the national capital since February this year.
Air quality in Delhi, which remained normal till Sunday evening, went dangerously beyond the permissible limits in the city as bursting of firecrackers picked up late at night. As per official data collated by AirVisual, AQI in Delhi, which was recorded at 163 at 5:30 pm, touched 1,005 around 11:30 pm.
An AQI between 0-100 is considered to be in the ”good+satisfactory" bracket, and 101-200 is termed as ”moderate", while AQI between 201-300, 301-400, and 401-500 falls in the “poor”, “very poor”, and "severe” category, respectively. Anything above 500 is "severe-plus emergency" category. According to World Health Organisation’s (WHO) standards, an AQI of 10 is considered as safe.
In several locations, the air quality was recorded to be far worse, as per Delhi Pollution Control Committee’s (DPCC) real-time data. For instance, in Jawaharlal Nehru Stadium area, concentration of major pollutant PM 2.5 — fine particles having a diameter of less than 2.5 micrometers and capable of reaching deep into lungs — touched 1,569 µg/m3 at 12 am. Similarly, PM 2.5 levels in Anand Vihar touched 1,549 µg/m3 at 2 am on Monday.
Unlike AQI, which is an aggregate of multiple pollutants, PM 2.5 levels over 250 fall in the ‘severe’ category while anything over 380 is hazardous.
However, with a drop in pollution levels on Monday morning, the overall 24-hour-average of AQI of 368 released by the Central Pollution Control Board (CPCB) at 4 pm on Monday is the best post-Diwali figure in the capital since 2015.
VK Shukla, head of air quality lab at CPCB, said that favourable weather conditions in the capital ensured that air quality in the capital did not dip as much as it had in previous years during the same time.
“However, the weather conditions aren’t favourable right now — the conditions are quite calm and if people burn crackers today [Monday evening], then it might result in the AQI increasing,” he explained.
“While it is too early to point to the exact reasons, the fact that we had teams on the grounds and that people used green crackers instead...it could have helped in the improve AQI,” Shukla added.
In 2018, AQI was recorded to be at 390 on the day after Diwali whereas it had crossed the 400-mark in 2017, as per CPCB’s air quality bulletin. AQI was far worse at 445 in 2016 while in 2015, it was measured at 360.
With alarming levels of air pollution in Delhi during Diwali, which falls around the stubble burning season in Punjab and Haryana — another major contributor to Delhi’s poor air quality, the Supreme Court had last year banned conventional firecrackers while putting a two-hour limit for bursting them on Diwali. The apex court had said that there was a need to ensure that only ‘green crackers’ are manufactured.
Meanwhile, apart from Delhi, areas surrounding the national capital also recorded average AQI levels in the ‘very poor’ category. Noida at 397 was the worst followed by Ghaziabad at 392, Gurgaon at 372 and Faridabad at 358.
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