Delhi remains one of the most polluted cities globally in 2024, with severe air quality issues driven by local and regional factors such as vehicle emissions, industrial pollution, and stubble burning. Despite past improvements from policy interventions like CNG buses, pollution spikes every winter due to temperature inversion and inadequate year-round measures. Sustainable solutions require continuous monitoring, political will, and public participation to treat clean air as a fundamental right
Delhi, India's capital city, continues to grapple with severe air pollution, ranking among the most polluted cities worldwide in 2024. This article delves into the current state of air quality in Delhi and other Indian cities, explores the historical context of pollution control efforts, examines the causes behind the persistent smog, and discusses the necessary steps to achieve sustainable clean air.
According to the IQAir World Air Quality Report 2024, only 17% of the world's cities had acceptable air quality levels. Alarmingly, 13 of the top 20 most polluted cities were located in India, highlighting the country's significant air quality challenges.
Data from the Central Pollution Control Board and multiple air quality monitoring reports for 2025 reveal that the cleanest cities in India are those with the lowest Air Quality Index (AQI) values, primarily influenced by particulate matter PM10 and PM2.5.
During the winter session from October 1, 2023, to January 31, 2024, North and East India experienced the highest pollution levels, with average PM2.5 concentrations of 89.9 and 85.9 micrograms per cubic meter, respectively. In contrast, South India maintained relatively cleaner air.
Within the northern region, the National Capital Region (NCR) recorded even higher pollution levels, averaging over 113 micrograms per cubic meter.
The Center for Science and Environment's State of Environment Report 2024 illustrates that southern states benefit from their extensive coastlines, which aid in dispersing pollutants. However, exceptions exist, such as Delhi and Chandigarh, which recorded average PM2.5 levels of 188 and 100.9 micrograms per cubic meter, respectively.
States like Bihar and Haryana topped the pollution charts, followed closely by Uttar Pradesh, Rajasthan, and Punjab. Conversely, Karnataka emerged as the cleanest state with winter averages of 32 micrograms per cubic meter, followed by Kerala at 33.4 micrograms per cubic meter.
Among the 20 cleanest cities, 11 are in Karnataka, three each in Tamil Nadu, two in Madhya Pradesh, and one each in Sikkim, Chhattisgarh, Kerala, and Assam. Residents of these cities enjoy better air quality and are encouraged to appreciate this advantage.
On the other hand, 11 of the 20 most polluted cities are in the National Capital Region, underscoring the severity of air pollution in and around Delhi.
Delhi, with a population exceeding 20 million, is one of the world's most polluted megacities. Every winter, the city faces a recurring crisis characterized by smog, school closures, flight delays, and widespread use of masks for clean air rather than protection from COVID-19.
In the late 1990s, Delhi became one of the first cities globally to convert its public bus fleet entirely to CNG, a bold move led by the Supreme Court and supported by the Center for Science and Environment (CSE). This initiative resulted in a dramatic reduction in pollution levels, demonstrating the effectiveness of strong policy measures.
Despite past successes, Delhi's air quality has deteriorated significantly over the last decade. Every winter, pollution levels spike due to a combination of local, regional, and seasonal factors.
During winter, a phenomenon called temperature inversion traps pollutants near the ground, exacerbating smog. This phenomenon is less prevalent in South India due to warmer winter temperatures.
According to CSE data, the contributions to Delhi's air pollution are as follows:
This diverse mix of sources makes addressing Delhi's pollution particularly challenging.
Geographer Rohit Ni describes Delhi's air pollution as a problem of perennial pollution, where efforts to combat pollution are often reactive and limited to the worst months. Temporary measures like vehicle rationing schemes do not address the deeper structural causes, such as:
Ni argues that unless clean air is treated as a year-round political priority rather than a seasonal emergency, the crisis will persist.
Environmentalist Sunan Narayan, director of the Center for Science and Environment, emphasizes that the fight for clean air is continuous and requires:
Clean air must be democratized and recognized as a public good, akin to water, roads, or schools. It should not remain a privilege of the elite but become a fundamental demand of the public.
Delhi's air pollution crisis in 2024 is a complex issue rooted in multiple factors that require comprehensive and sustained action. Past policy successes demonstrate that change is possible, but reversing the recent deterioration demands year-round commitment, structural reforms, and collective responsibility. Only through continuous efforts and political prioritization can Delhi and other Indian cities hope to breathe cleaner air in the future.
