Pollution down but it remains ‘severe’
SOME RELIEF Though air appears to have improved marginally, experts still unsure about the impact of the SC ban
NEW DELHI : Just like last year’s Diwali, the levels of air pollution in the city may have entered the “severe” category again, however, there was some relief for Delhiites as the air appeared cleaner in comparison.
The Central Pollution Control Board (CPCB) released data showing that compared to last year, there was a significant fall in volume of particulates PM2.5, PM10 and gaseous pollutant SO2 (sulphur dioxide) recorded by its stations l ocated across the national capital on the night of Diwali.
However, the volume of pollutants were almost identical, at places higher, when placed against the figures of 2014 or 2015, making it difficult to attribute the marginal dip to any particular factor, such as the ban on the sale of firecrackers imposed by the Supreme Court.
The CPCB’S air quality index (AQI) on Diwali day had a score of 426 last year, which falls in the “severe” or the “most polluted” category. This year it was 326, in the “very poor” category, which is slightly better. However, the AQI of the city on Friday morning was 403, in the “severe” category, same as before.
“From 8pm, pollution readings started going up. At midnight, it was the highest. Since the AQI takes into account 24-hour pollution data, from 4pm Diwali day to 4pm the day after, it includes the peak pollution period. It will take another 24 hours for things to normalise,” Dipankar Saha, head of CPCB’S air lab, said.
According to the Centre for Science and Environment (CSE), the pollution levels worsened on Friday morning due to calm wind and higher moisture in the air — as was predicted.
“Since October 1, PM2.5 levels have largely hovered around ‘poor’ to ‘very poor’ categories. But this breached the emergency level on Diwali night,” Anumita Roychowdhury, executive director-research and advocacy, CSE, said.
The analysis also showed that this year’s Diwali morning and evening showed promising signs, with little or no firecrackers being burst across many locations in the initial hours of the night. But as the celebrations picked up, air quality dipped.
The firecrackers also led to a dramatic spike in levels of sulphur dioxide. The SO2 levels, that otherwise remain very low, increased by more than three times in several locations, including RK Puram, Shadipur and Punjabi Bagh, the CSE analysis showed.
“On October 17-18, the SO2 levels in Delhi were less than 50 microgramme per cubic metre. But on Diwali night, the hourly levels increased alarmingly to 183 microgramme per cubic metre. This is a direct indicator of impact of crackers,” it said.
The spike in pollution happened despite Delhi Police saying it seized 3,775 kg of crackers in raids till Friday afternoon. “A total of 88 FIRS were registered in connection with these illegal sales. We also arrested 88 people,” said a Delhi Police officer.
Experts said that the ban has the potential to have an impact in preventing the pollution from episodic sources of pollution like Diwali.“the need today is to curb the major sources of pollution along with curbing the episodic sources, such as Diwali firecrackers, to achieve breathable air throughout the year,” Sunil Dahiya, campaigner, Greenpeace India said.
The Delhi Pollution Control Committee (DPCC) released data based on monitoring at 16 sites. According to its data, levels of PM2.5 and PM10 showed a marginal dip compared to last year.