Delhi’s air quality reached the ‘very poor’ category with an AQI of 366 after Diwali. Many monitoring stations recorded severe pollution levels as visibility fell across the capital. A bench of justices said, “the earlier complete ban had neither significantly improved air quality nor prevented the illegal sale and use.”
At 5.30pm, Delhi's air quality was already in the 'very poor' category, even before firecrackers were burst in large numbers. The overall AQI stood at 376, under the 'very poor' category. The Capital also witnessed reduced visibility.
Of the 59 monitoring stations, 12 recorded air quality in the 'severe' category, while 22 reported 'very poor' air quality. The Air Quality Early Warning System (EWS) for Delhi had forecast that air quality was likely to deteriorate to the 'severe' category from November 9 and remain there for the next few days.
By 7pm, the city's AQI stood at 371, in the 'very poor' category. Of the 59 monitoring stations, 19 were in the 'severe' category, seven in the 'poor' category and the remaining 33 in the 'very poor' category. According to a PTI report, several people took to social media to report smelling smog and firecracker smoke in the air, while others flagged reduced visibility.
At 9pm, Delhi's AQI, according to official data, stood at 370, while the HT Pollution Dashboard reported it at 389. Both readings were in the 'very poor' category. The difference in the figures is because the official AQI calculation includes 20 more monitoring stations than the HT Pollution Dashboard's comparison of stations that reported data last Diwali. Most of these additional stations recorded cleaner air, pulling the official average down by 19 points.
By 10pm, the city's AQI stood at 371, under the 'very poor' category, according to the CPCB. Of the 59 monitoring stations, 20 were in the 'severe' category, 33 reported 'very poor' air quality and six were in the 'poor' category. Sonia Vihar recorded the highest AQI at 463, placing it in the 'severe' category.
The CPCB classifies an AQI of 0-50 as 'good', 51-100 as 'satisfactory', 101-200 as 'moderate', 201-300 as 'poor', 301-400 as 'very poor' and 401-500 as 'severe'.
A bench of justices MM Sundresh and PB Varale said it was opting for a regulated approach rather than a blanket prohibition, noting that the earlier complete ban had neither significantly improved air quality nor prevented the illegal sale and use of conventional firecrackers. It also pointed out that restrictions had repeatedly been violated, with conventional crackers being sold under the guise of green firecrackers.
The court observed that while firecrackers undoubtedly contributed to pollution, measures taken by authorities, either following judicial directions or on their own, had failed to achieve the desired results. It stressed that the problem lay in implementation and called for better coordination among stakeholders and sustained monitoring beyond the festive season.
On November 3, the Supreme Court, taking note of a Hindustan Times report exposing the open sale of conventional and unauthorised firecrackers in Delhi markets, asked the law officer to look into the matter and ensure that necessary measures were taken. The development brought the focus back on enforcement even as the court had relaxed its blanket prohibition.
What were the main sources of pollution?
PM2.5 was the predominant pollutant in Delhi on Sunday, with emissions from firecrackers adding to the particulate matter in the air.
According to the Decision Support System (DSS) for Delhi, the transport sector was the biggest contributor to the city's pollution on Sunday, accounting for 19% of the total. Stubble burning accounted for an estimated 3.5%, with its contribution forecast to fall to around 2.99% on Monday.
Weather and air quality experts have attributed the anticipated deterioration in air quality to a combination of vehicular emissions, Diwali-related celebrations and the peak stubble-burning season in neighbouring states.
Unfavourable weather conditions are further aggravating the situation by slowing the dispersal of pollutants. According to the Air Quality Early Warning System (EWS), a ventilation index below 6,000 square metres per second, combined with an average wind speed of less than 10 kilometres per hour, makes it difficult for pollutants to disperse.