India’s capital, Delhi, has been suffering from poor Air Quality Index (AQI) levels during certain periods every year. On 15 December 2025, the AQI was recorded as high as 452. An AQI above 400 signifies “severe” to “hazardous” air quality, meaning the air is toxic and can cause immediate health effects such as burning eyes, coughing and breathlessness, while significantly increasing the risk of respiratory infections and other illnesses.
Over the five-year period from 2020 to 2025, Delhi reported an average annual AQI of below 200, which is considered acceptable. However, during specific months each year, the AQI has reached alarming levels exceeding 450. Whenever Delhi’s air quality crosses the 400 mark, particularly during winter months, it becomes a matter of serious concern, as is evident at present. There is a growing apprehension that such episodes may become a permanent feature in the coming years, as a comprehensive and lasting solution to this grave issue has yet to be conclusively formulated and implemented.
As the capital of India, hosting embassies and consulates from more than one hundred countries and having a population density of approximately 11,600 persons per square kilometre, persistently high AQI levels have become a source of embarrassment for the nation. A permanent solution is therefore imperative to address this critical challenge.
A careful analysis of the situation suggests that while the Delhi government has made sincere efforts to implement various measures, these interventions often appear to be reactive and short-term in nature. They are typically introduced as knee-jerk responses during periods when AQI levels reach alarming heights, as witnessed once again in the last quarter of 2025.
It has often been argued that Delhi’s air quality deteriorates during winter primarily due to stubble burning, a traditional practice used to clear paddy residue and prepare fields for the next crop in neighbouring states such as Haryana, Punjab and Uttar Pradesh. The government has introduced several measures to curb this practice. In a statement to Parliament, the Ministry of Environment claimed that Punjab and Haryana collectively reduced fire incidents by 90 per cent in 2025 compared to 2022. However, some researchers have disputed this claim, stating that the actual reduction in the land area burned was more gradual—around 30 per cent, declining from approximately 31,500 square kilometres in 2022 to about 19,700 square kilometres in 2025 as of 25 November.
Nevertheless, it is evident that stubble burning has declined substantially. Despite this sharp reduction, it has not led to a corresponding improvement in Delhi’s AQI, indicating that stubble burning alone is not the decisive factor behind the city’s severe air pollution.
Whenever Delhi’s AQI rises above 400, the government adopts a multi-pronged approach, routinely implementing regulatory measures such as the Graded Response Action Plan (GRAP), the use of RECD systems or dual-fuel kits in diesel generator sets, cleaner fuels in industries, a shift to electric vehicles, CNG and BS-VI diesel in the transport sector, and dust control measures at construction and demolition waste sites. However, current ground realities show that even these multiple interventions have failed to produce a sustained reduction in AQI levels.
Several fundamental factors contribute to Delhi’s air pollution problem. Delhi is a landlocked city, and such cities are inherently more prone to air pollution due to the absence of natural atmospheric ventilation and dispersion mechanisms that benefit coastal cities, such as regular sea breezes and stronger winds. Additionally, Delhi’s location in the Indo-Gangetic Plain exposes it to cross-border pollution from other parts of India, further compounding the problem. Winter weather conditions, including temperature inversions and calm winds, exacerbate the situation by trapping pollutants close to the surface and intensifying smog.
These are structural and environmental factors that lie largely beyond the control of the Delhi government. While various measures have been introduced over the years, past experience clearly shows that these steps alone are insufficient to bring AQI levels down to acceptable limits. This reality suggests that the government must think beyond conventional solutions to arrive at a permanent and effective strategy.
Delhi’s high population density is often cited as a contributing factor, yet population decongestion as a remedial measure is impractical. At present, the government tends to activate multiple control measures only when AQI levels peak, rather than enforcing them consistently throughout the year. This reactive approach has proven ineffective.
There is a strong case for halting construction activity in Delhi on a permanent basis. Registration of new vehicles should also be stopped, and stricter limits imposed on the number of vehicles permitted on the roads. Efforts to eliminate stubble burning in neighbouring states must be intensified to achieve complete eradication. Offices and commercial establishments, whether public or private, should be encouraged to relocate outside the Delhi National Capital Region, and no new offices or establishments should be permitted within Delhi.
All measures introduced so far should be enforced permanently and throughout the year, rather than only during peak pollution periods. Since the natural factors that make Delhi pollution-prone will persist indefinitely, the countermeasures to combat air quality deterioration must also be permanent and continuous. In essence, Delhi must aim to reach a point of stagnation in growth in order to safeguard public health and environmental sustainability.
