Delhi recorded the worst air quality in India during winter 2024-25: Report

With an average PM2.5 value of 159 μg/m³ during the winter of 2024-2025, Delhi was the most polluted city in India. According to the analysis, Aizawl in Mizoram was the cleanest city

Delhi Air Quality 2024-25: During the winter of 2024-25, Delhi recorded the highest pollution levels in India, with an average PM2.5 concentration of 159 μg/m³, making it the country's most polluted city of the season. Aizawl, Mizoram, recorded the lowest winter-average PM2.5 level at 7 μg/m³, earning the title of the cleanest city in India.

 

The national capital was the most polluted city last year too, with a higher average of 171 μg/m³. A report titled "Winter Ambient Air Quality Snapshot of India", released by the Centre for Research on Energy and Clean Air (CREA), revealed that 173 out of 238 cities recorded winter-average PM2.5 levels exceeding India’s National Ambient Air Quality Standards (NAAQS) of 40 μg/m³. 

 

In addition to sharing her plans to clean up the capital city, newly elected Delhi Chief Minister and Shalimar Bagh MLA Rekha Gupta recently stated that her government and the Center are collaborating to address "major issues".

Chief minister on Pollution in Delhi 

"If the Delhi government starts working with the Centre without losing any time, it will definitely get what it had been devoid of during the AAP regime," Gupta said at the India Today conclave on Friday, highlighting the major projects her government is working on to improve Delhi's air, water, and infrastructure. She also said that her government is a part of the "Narendra Modi team." 

 

“Our government will work with the governments of the neighbouring states to fix the issue of air pollution, in addition to fixing the in-house problems. We have the solution to Delhi's pollution," she added. "Work has already begun to plant saplings and gradually replace the landfills with greenery and parks," Gupta promised to convert Delhi’s massive landfills into green belts. 

Air Pollution of Delhi, NCR in Winters 2024-25

With a greater average of 171 μg/m³ during the previous winter (2023–24), Delhi maintained its position as the most polluted city in India. According to the CREA report, winter-average PM2.5 levels in 173 of 238 cities were higher than the country's National Ambient Air Quality Standards (NAAQS), which are 40 μg/m³. 

 

The magnitude of the air quality issues is further highlighted by the fact that none of the 238 cities examined achieved the WHO recommended level of 5 μg/m³.

 

Winter in India is defined as October 1, 2024, through February 28, 2025 (winter 2024-25). In winter 2024–2025, Byrnihat in Meghalaya came in second, with a PM2.5 concentration of 157 μg/m³. In addition, Gurgaon, Noida, Hajipur, Ghaziabad, Patna, Asansol, Durgapur, and Charkhi Dadri were among the top 10 most polluted cities.

Top 10 most polluted cities in India 

Along with Delhi, the top 10 most polluted cities are found in Uttar Pradesh, Bihar, Haryana, West Bengal, and Assam. At the state level, all of the monitored cities in Rajasthan (34 cities), Bihar (24 cities), and West Bengal (7 cities) exceeded NAAQS. 

 

Similarly, a large percentage of cities in Uttar Pradesh (15 out of 20), Odisha (15 out of 16), and Maharashtra (30 out of 31 cities) had winter PM2.5 levels above the national standard. 

 

100 cities appeared in the top 10 most polluted cities at least once over the 151-day winter season. 44 of these cities made at least 10 appearances. Delhi (105 days), Hajipur (80 days), Ghaziabad (52 days), and Bahadurgarh (47 days) were the next cities with the highest recurrence, Byrnihat (111 days).

Top 10 least polluted cities in India 

Three cities from Tamil Nadu, one from Mizoram, and six from Karnataka were among the top ten least polluted cities. The WHO recommended limit was surpassed by all 98 NCAP cities with Continuous Ambient Air Quality Monitoring Stations (CAAQMS) data, with 78 recording winter-average PM2.5 levels above NAAQS. Similarly, 95 of 140 non-NCAP cities exceeded NAAQS, and all stayed above WHO recommendations. This demonstrates that air pollution affects a larger range of metropolitan regions and is not just a problem in NCAP cities. 

 

Manoj Kumar, an analyst at CREA, stated in a press release that "Reducing winter air pollution is essential to bringing down the annual average pollution levels in Indian cities. CREA’s winter air quality analysis highlights that both NCAP and non-NCAP cities face high pollution levels, and the issue extends far beyond NCR, affecting regions across India. The upcoming NCAP revision presents a crucial opportunity to include more cities under the programme and implement targeted mitigation measures that focus on cutting pollution at the source, such as enforcing stricter emission standards rather than only addressing its effects".