PremiumMost parts of Delhi recorded poor air levels - which can still significantly harm people's health in the long term but didn't hit the severe category.
Delhi recorded "very poor" air quality on Tuesday, the day after Diwali, but surprisingly, the residents were not seen gasping for breadth like every year around this time. The agencies tracking the same reported that pollution levels for Tuesday were actually the lowest since 2015.
Most parts of the city recorded "poor" or "very poor" air levels - which, to be sure, can still significantly harm people's health in the long term - but didn't hit the "severe" category.
Delhi's AQI on the day after Diwali stood at 360 in 2015, 445 in 2016, 403 in 2017, 390 in 2018, 368 in 2019, 435 in 2020 and 462 in 2021.
Experts attribute this to a mix of factors including favourable weather conditions. And pointed out that favourable meteorological conditions that diluted the effect of the fireworks and stubble burning.
The firecracker emissions pushed the PM2.5 concentration at most places in the capital over 550 micrograms per cubic metre by 1 am. However, the PM2.5 levels dropped below 150 micrograms per cubic metre by 4 pm due to warm and windier conditions, which are favourable for the dispersion of pollutants.
"Early Diwali, with slightly better meteorological conditions and comparatively lower fire counts, had a lower pollution base compared to the last few years," Sunil Dahiya, an analyst at the Centre for Research on Energy and Clean Air (CREA), said.
"Bursting of firecrackers led to a sharp increase in the air pollution with the PM2.5 concentration, on an average, jumping to 540 micrograms per cubic metre across Delhi by 12:30 am. Several monitoring stations in the capital recorded PM2.5 levels above 950 micrograms per cubic metre between 10 pm and 1 am," Dahiya told PTI.
PM2.5 are fine particles that are 2.5 microns or less in diameter and can travel deep into the respiratory tract, reaching the lungs and entering the bloodstream.
Meanwhile, Chief Minister Arvind Kejriwal said the results of the residents' efforts to curb pollution in the city are encouraging, but there is still a long way to go.
However, the neighbouring cities of Ghaziabad (266), Noida (299), Greater Noida (272), Gurugram (292) and Faridabad (289) reported "poor" air quality.