Delhi logs best AQI for December but worst in 5 years for 2024

New Delhi: While the current month provided a silver lining as the cleanest Dec on record, pollution levels in the capital during 2024 were the worst in five years. The year is set to record an average AQI of 209, a deterioration from last year’s mean of 204 and tied with two other years as the worst AQI since 2019, report Amit Bhattacharya & Priyangi Agarwal.

Although 2021 and 2022 also logged an annual AQI of 209, 2024 was the first year since 2018 that saw no ‘good air day’. The year recorded 17 severe air days, highest since 2021. Experts say the slide shows govt’s actions haven’t proved effective in denting the region’s toxic air quality.

December, along with Feb and Aug, rare high points

First, the good news. This Dec has been cleanest ever, with an average AQI of 294, since the index started being recorded in 2015. This was the first time that the average AQI in Dec dipped below 300. Strong winds in the first fortnight of the month and widespread rain last week helped keep AQI low.

Dec 2024 recorded eight ‘moderate’ days, the highest number of moderate air days ever recorded in Dec. It also witnessed six ‘severe’ days, including one severe plus day when AQI touched 451 on Dec 19. The month saw four consecutive days, making it the worst streak in three years.

Dec, along with Feb (cleanest on record) and Aug (2nd cleanest after 2020), were the rare highlights in a year when the average air quality fell to its worst since 2019. Jan 2024 set the tone, logging the second highest AQI on record after 2016. Four other months of the year — May, Sept, Oct and Nov — saw the worst average AQIs for the respective months since at least 2021.

This deterioration in pol- lution not only has implications for the health of Delhi-NCR residents but also shows that the anti-pollution measures haven’t been able to improve air quality over the past three-four years.

“The measures on the ground have worked to the extent that these have kept annual pollution at nearly the same level despite a sharp rise in emissions after Covid. However, for an improve- ment in air quality, stricter measures have to be taken and scaled up to all parts of NCR and beyond. There’s also an urgent need to generate better and more granular data for more targeted action,” said Dipankar Saha, former head of the air laboratory division of CPCB.

Anumita Roychowdhury, executive director, research and advocacy, Centre for Science and Environment (CSE), said, “Implementation of the multi-sector clean air action targeting vehicles, industry, waste management, solid fuel burning, and construction needs to speed up manifold to make a difference to the overall air quality.”

Relying on quick-fix measures and favourable meteorology will not lead to a sustained reduction in air pollution, said Sunil Dahiya, founder and lead analyst at the think tank, Envirocatalysts.

“To truly address this crisis, we need absolute emission load reductions across all sectors in Delhi-NCR and its larger air-shed, supported by time-bound sectoral and geographical targets. This demands decisive action on industrial emissions, vehicular pollution, waste management and a transition to clean energy. Without these comprehensive steps, achieving long-term air quality improvement will remain a distant goal," he said.