Delhi's AQI Problem

Delhi’s struggle with air quality remains one of India’s most pressing urban environmental challenges. Every winter, levels of particulate matter and toxic pollutants soar, pushing the city’s Air Quality Index (AQI) into the ‘very poor’ and ‘severe’ categories and triggering health warnings for millions of residents. The causes are complex and seasonal, involving local emissions, regional pollution sources, and specific weather conditions that trap smog over the city.

The AQI is a composite measure that reflects concentrations of harmful pollutants such as PM2.5 and PM10. In late December 2025, monitor readings recorded days when the average AQI exceeded 400, categorised as ‘very poor’ or worse, leading to public concern and protests at landmarks like India Gate. Poor air quality is linked to respiratory stress, cardiovascular concerns and even long-term health risks, particularly for vulnerable groups such as children and the elderly. The geographic and climatic context exacerbates the problem. Delhi lies in a basin between the Himalayas and the plains, where winter temperature inversions can trap pollutants close to the ground. Vehicular emissions, construction dust, industrial outputs and regional crop burning contribute layers of particulate matter.

In response, policymakers at multiple levels have crafted a series of interventions to curb the worst impacts of pollution. The Graded Response Action Plan (GRAP) is one of the central instruments for managing air quality in the National Capital Region (NCR). First introduced by the Ministry of Environment, Forests and Climate Change in 2017, this plan sets out a tiered set of actions that are triggered based on real-time AQI levels. It divides responses into stages ranging from moderate to severe pollution, each with escalating restrictions.

Under GRAP’s higher stages, authorities can enforce restrictions on vehicular access, halt construction and demolition activities, and curtail certain industrial operations. When pollution reached particularly hazardous levels in late 2025, Stage IV measures were activated. These included bans on older, more polluting vehicles, restrictions on truck entry unless they use cleaner fuels such as compressed natural gas or electricity, and suspension of non-essential construction. Government and private offices were directed to operate with reduced on-site staff and schools were moved partially to hybrid learning models to reduce exposures.

City authorities have also implemented stricter year-round controls. The “No PUCC, No Fuel” campaign mandates that vehicles must hold a valid Pollution Under Control Certificate before refuelling, and compliance is strictly monitored. The Delhi government approved fresh environmental governance measures that include allocating funds for rejuvenation of water bodies and establishing facilities like an e-waste park that adheres to environmental norms, reflecting an effort to embed pollution control in broader urban management.

Efforts to curb emissions from transport have not been limited to restrictions. Delhi has encouraged the adoption of cleaner fuels and electric vehicles. Public transport has gradually transitioned to compressed natural gas (CNG) and electric buses, reducing reliance on diesel and petrol. Incentives have been offered for electric vehicle uptake among private citizens, and regulators have pushed for integration of electric mobility into app-based taxi and shared transport services.

Regulations also pile onto construction dust, an often overlooked but significant source of particulate matter. Delhi’s government has tightened controls that require effective dust suppression at construction sites, use of anti-smog technology, and covering of waste materials to prevent fugitive dust from entering the urban atmosphere.

Despite these measures, challenges remain. Enforcement capacity has been called into question, with reports of staff shortages at pollution monitoring bodies hindering on-ground action. Moreover, the phenomenon of regional pollution means that Delhi’s air quality is affected by emissions from neighbouring states, particularly during the harvest season when crop residue burning spikes. These extrinsic factors mean that even stringent local policies sometimes yield only incremental improvements.

Public perception reflects the urgency. Protests demanding stronger government action and greater accountability have drawn attention to the human toll of persistent smog, pushing policymakers to confront political and administrative inertia. At the same time, authorities highlight that air quality patterns show some positive signs, with occasional days moving into better AQI categories thanks to sustained interventions and favourable meteorological conditions.

Looking ahead, experts argue that a combination of structural reforms and cooperative regional policies is necessary. Stronger integration between Delhi and neighbouring states under regional clean-air frameworks, investment in advanced monitoring and forecasting, and sustained public engagement are seen as critical to transforming Delhi’s air quality over the long term. Comprehensive action is required not only during crisis periods in winter but throughout the year to create a healthier urban environment for its millions of residents.

In sum, Delhi’s air quality crisis has driven a complex policy response involving emergency measures, regulatory innovation, and longer-term interventions. While progress is visible in some metrics, the city’s struggle against smog underscores the scale of the environmental and governance challenge ahead.