Delhi this year recorded its most polluted December since 2018, reported The Indian Express on Wednesday.
The PM2.5 level averaged 211 micrograms per cubic metre of air during the month. In December 2018, it was 229.3 µg/m3.
PM2.5 refers to tiny airborne particulate matter that is about 30 times smaller than the width of a human hair and can easily be breathed into the lungs and the bloodstream.
India’s National Ambient Air Quality Standards prescribe a “safe” PM2.5 limit of 60 μg/m3 over a 24-hour period. The World Health Organization prescribes 15 μg/m3.
In the corresponding period in 2019, the level was 205.9 µg/m3 and 194.6 µg/m3 in 2020. In 2021, the PM2.5 level reached 200 µg/m3 in December. In December 2022, it dipped to 174.3 µg/m3, rose to 201.6 µg/m3 in 2023 and was 169.9 µg/m3 in 2024.
Citing data from the Central Pollution Control Board, The Indian Express reported that the average daily PM2.5 had crossed 250 µg/m3 for more than 31% of the days in December this year. It exceeded 150 µg/m3 for more than 82% of the month.
The highest daily average was observed on December 14 at 392.6 µg/m3. The previous highest PM2.5 pollution recorded above this level was 402.9 µg/m3 on December 23, 2018.
Manoj Kumar, pollution analyst at the Centre for Research on Energy and Clean Air, told the newspaper that the absence of stubble burning during peak pollution days in the national capital “makes it evident that Delhi’s air pollution is also being driven by persistent, year-round emissions”.
“This calls for enforceable, sector-specific emission reduction targets for industry, transport, power plants, and other major sources, instead of short-term or seasonal responses,” he added.
Air quality deteriorates sharply in the winter months in Delhi, which is often ranked the world’s most polluted capital. Stubble burning in Punjab and Haryana, vehicular pollution, along with the lighting of firecrackers during Diwali, falling temperatures, decreased wind speeds and emissions from industries and coal-fired plants contribute to the problem.
Delhi’s ‘very poor’ AQI
On Wednesday, the Air Quality Index in Delhi stood at 377 at 12.05 pm, according to data from the Sameer application, which provides hourly updates from the Central Pollution Control Board.
An index value between 301 and 400 indicates “very poor” air. Between 401 and 450 indicates “severe” air pollution, while anything above the 450 threshold is termed “severe plus”.
An AQI in the “severe” and “severe plus” category signifies hazardous pollution levels that can pose serious risks even to healthy individuals.
In December, Delhi saw five days when the AQI reached above 400.
The air quality in the national capital had worsened to the “severe plus” category between December 13 and December 15.
Delhi and the National Capital Region are under Stage 3 restrictions under the Graded Response Action Plan to curb pollution.
GRAP is a set of incremental anti-pollution measures that are triggered to prevent further worsening of air quality once it reaches a certain threshold in the Delhi-NCR region.
Stage 3 measures include a ban on non-essential construction work and the closure of stone crushers and mining activities, in addition to the measures already imposed under Stage 1 and Stage 2.
They also include the shifting of primary school up to Class 5 to hybrid mode. Parents and students have the option to choose between offline and online classes wherever available.
Also read: Why air quality numbers in Delhi vary widely
You’ve read Scroll.
Now help sustain it
Scroll is funded by readers, not corporate owners. If you believe our work matters, support our newsroom. Become a member today!
We’re not driven by clicks or corporate interests – just honest, independent reporting. Keep us going. Support Scroll today!