For the second consecutive year, the air quality in Delhi got worse in 2024, with the annual PM 2.5 levels going up. A new report from the Centre for Science and Environment (CSE) says that even though the amount of stubble burning (burning of crop residue) in nearby states like Punjab and Haryana went down a lot, the air quality still got worse.

The CSE’s report on winter air quality, released on Monday, showed that the annual PM 2.5 levels in Delhi went up to 104.7 micrograms per cubic meter (µg/m2) in 2024. This was a 3.4% increase from 2023. The level is more than twice the safe limit for air quality, which is set at 40 µg/m2. Bottom of Form

Stubble burning in Punjab, Haryana, and Delhi decreased by 71.2% from October to December in 2024, but the air quality still got worse. The study found that while the average PM 2.5 levels during these months were similar to previous years, the highest pollution levels increased significantly. In 2024, the peak pollution levels went up from 580 µg/m³ to 732 µg/m³, which is a 26% rise.

Worsening air quality signals need for long-term solutions

The CSE study, written by Anumita Roychowdhury, Executive Director of Research and Advocacy, and Sharanjeet Kaur, used real-time air quality data from monitoring stations across Delhi-NCR.

Roychowdhury stated, "The worst station-level peak this season was 9% lower than the highest ever recorded—at 806 µg/m³ during the 2018 winter.” The report also pointed out two significant smog events that added to the poor air quality.

Even though stubble burning has dropped significantly, Roychowdhury explained that the rising pollution shows a bigger problem. She said, "This cannot be seen as just a one-time issue caused by weather changes. The continuous rise shows that pollution is increasing in the region." The study suggests that local and nearby sources of pollution, like vehicles, factories, burning of waste, and dust from construction, have undone the progress made in improving air quality over the past ten years.

According to CSE's analysis, Delhi could have seen better results, including stable or declining annual PM 2.5 levels, if stricter actions had been taken. Effective implementation of the Supreme Court’s directives on energy transition and transport could have helped to reduce pollution from industry and vehicles. The CSE emphasised that “action has to move much beyond reactive emergency measures during winter."

Roychowdhury further pointed out that the increasing levels for two consecutive years, even with less stubble burning, show that systemic changes are required to address emissions from various sources throughout the year.

The state of Delhi’s ‘good’ and ‘bad’ air days

The CSE's study also looked at how many days had "good" and "bad" air quality in 2024. About 121 days met the National Ambient Air Quality Standards (NAQMS), which is similar to the air quality levels in 2019, when Delhi had its second-worst yearly average of 109.1 µg/m2. Although the number of "good" air days went up from 25 in 2023 to 29 in 2024, this improvement was overshadowed by a rise in "bad" air days.

The number of days with "very poor" or "severe" air, meaning very high pollution, went up from 107 in 2023 to 111 in 2024. Also, there was no improvement in the number of "poor" or "very poor" air quality days during winter. This stayed at 57 days, showing no progress during the critical winter months.

The report suggests that Delhi needs long-term solutions to deal with the increasing pollution. Short-term actions or quick fixes will not be enough to solve the air pollution problem in the city.