Urban Acres
Delhi Air Pollution Is a Year-Round Governance Failure, Not a Winter Crisis
Delhi’s air pollution problem is often treated as a winter emergency, but the evidence cited in a recent report points to a more persistent urban governance challenge: most of the pollution is generated within the city and the wider region throughout the year. According to a Centre for Science and Environment analysis of data from the Indian Institute of Tropical Meteorology’s Decision Support System, local sources account for 80 to 85 per cent of Delhi’s pollution. Vehicles are the largest local contributor, with a 46 per cent share, followed by industry at 22 per cent.
That distribution changes the way Delhi’s air-quality crisis must be understood. External sources, including pollution transported from neighbouring regions, remain part of the problem, particularly during specific weather conditions. But the figures cited in the report indicate that the city cannot rely on seasonal restrictions or external explanations to deliver sustained improvement. The larger challenge is whether Delhi’s institutions can enforce controls on everyday urban activity: traffic, industrial operations, construction, road dust, household fuel use and waste burning.
The seasonal framing has shaped both public attention and administrative response. Measures such as restrictions on truck entry, intensified inspections and emergency pollution-control actions are generally associated with the period when air quality deteriorates sharply in winter. The report argues that this approach leaves a gap during the rest of the year, allowing emissions to accumulate or remain poorly controlled until adverse weather makes the problem visible.
The issue is not that winter measures are unnecessary. Delhi’s pollution becomes more hazardous when lower temperatures, weaker winds and atmospheric conditions trap pollutants close to the ground. The problem is that emergency action cannot substitute for routine enforcement. If the same sources operate throughout the year, an administrative system that becomes active only when the Air Quality Index deteriorates is responding to the symptoms of an established emissions problem rather than controlling its causes.
The source profile makes the institutional challenge clear. Vehicles account for 46 per cent of local emissions in the analysis cited by the report. This places mobility policy at the centre of air-quality management. Vehicle emissions are connected not only to the number of vehicles on Delhi’s roads, but also to congestion, fuel quality and compliance with pollution-control requirements. The report notes that the Commission for Air Quality Management has directed that vehicles without a valid Pollution Under Control Certificate should not receive fuel from May 2026. It also says that electric three-wheelers have been mandated for new registrations in Delhi and the National Capital Region.
These measures address compliance and fleet transition, but their effect depends on implementation. A rule requiring a valid certificate is meaningful only when testing is reliable, enforcement is consistent and violations carry consequences. Similarly, a shift towards electric three-wheelers can reduce emissions from a specific vehicle segment, but the report does not establish how quickly this will alter the overall vehicle contribution. What it does establish is that transport cannot be treated as a secondary issue in Delhi’s pollution-control framework.
Industry is the second-largest local source in the cited assessment, with a 22 per cent share. The report refers to separate directions issued by the Commission for Air Quality Management in 2026 for particulate emissions from industries. Delhi Pollution Control Committee monitoring also covers industrial sources, along with construction, generators, vehicles and open waste burning. This creates a broad regulatory responsibility, but it also raises the question of coordination between agencies and the consistency of field-level action.
The distinction between having rules and enforcing them is central to the city’s pollution problem. The report lists directions for controlling dust at construction and demolition sites, managing debris and operating mechanical road-cleaning machines. It also describes real-time pollution-source identification and forecasting arrangements under the Delhi Pollution Control Committee. These mechanisms indicate that the administrative system has formal tools for monitoring several major sources. The continuing pollution burden suggests that the existence of tools has not removed the implementation gap.
Construction and road dust together account for smaller shares in the figures cited: construction at 6 per cent and road dust at 3 per cent. Their percentages should not be read as evidence that these sources are unimportant. Construction activity is highly visible across Delhi, and dust from broken roads, uncovered material, demolition and poorly managed sites affects local neighbourhoods even when its citywide share is lower than that of vehicles or industry. The report specifically points to dust rising from a damaged road near Zakhira on Rohtak Road, illustrating how routine infrastructure conditions can become part of the pollution problem.
The governance implication is that pollution control cannot be limited to large, easily identifiable episodes. It must extend to the everyday management of streets and construction sites. Dust control depends on site inspections, covering materials, managing debris, maintaining roads and ensuring that contractors comply with prescribed procedures. Road-cleaning standards are useful only if equipment is deployed where it is required and if the outcome is monitored. These are municipal and regulatory functions that operate at street level, often far from the seasonal public debate over Delhi’s air.
The report also attributes 11 per cent of local pollution to domestic sources and 4 per cent to waste burning. These categories show that the problem is distributed across formal and informal urban systems. Household fuel use, waste collection failures and open burning cannot be addressed only through air-quality alerts. They require coordination between local administration, sanitation services, enforcement teams and communities. The supplied material does not provide a detailed assessment of the performance of these systems, but it identifies them as continuing components of the local emissions profile.
A further complication is the variation between pollution-source studies. To address this, the Commission for Air Quality Management has prepared a high-resolution emissions inventory and source-apportionment framework based on 500-by-500-metre grids, according to the report. The stated objective is to reduce differences between studies and create a more consistent scientific basis for identifying sources. This is important for governance because pollution-control resources cannot be targeted effectively if agencies are working from incompatible estimates of what is driving emissions in particular areas.
A grid-level framework could also make the city’s response more geographically precise. Citywide percentages identify broad priorities, but they do not show whether a neighbourhood’s exposure is driven mainly by traffic, construction, industry, waste burning or a combination of sources. The report does not provide the grid-level findings, so it is not possible from the supplied evidence to assess how the new framework changes enforcement priorities. Its significance lies in the attempt to connect scientific measurement with administrative action.
The timing of Delhi’s air-quality deterioration reinforces the argument for a year-round system. The report states that the city’s AQI was below 100 in August but crossed 170 by September, before a major fall in temperature. These figures are presented as an indication that pollution is not confined to the coldest months. They also challenge the assumption that winter weather alone creates Delhi’s air-quality crisis. Weather can intensify pollution, but emissions are present before the winter peak arrives.
That distinction matters for planning. If action begins only after air quality has already deteriorated, agencies are likely to rely on short-term restrictions rather than sustained source control. By September, traffic congestion, construction activity and industrial emissions are already part of the city’s daily operating pattern. A year-round plan would therefore need to treat air quality as a continuous municipal and regional management responsibility, rather than as a temporary emergency that begins with the onset of winter.
The policy landscape described in the report is already extensive. The Commission for Air Quality Management issues directions covering industries, vehicles, construction and demolition, road dust and fuel access. The Delhi Pollution Control Committee monitors multiple source categories and has systems for real-time source identification and forecasting. The challenge identified by the report is not an absence of policy instruments but their seasonal application and uneven enforcement.
This places responsibility across several layers of government. Air-quality regulators set standards and issue directions. The pollution-control committee monitors regulated sources. Municipal bodies are connected to roads, construction oversight, waste management and dust control. Transport authorities and enforcement agencies influence vehicle compliance and traffic conditions. Regional coordination is required for issues such as truck movement and crop-residue burning. The source material does not evaluate the performance of each institution separately, but it shows why no single agency can resolve the problem alone.
The regional dimension remains relevant even when local sources dominate. The report says neighbouring states must coordinate on timely disposal of crop residue to prevent open burning. However, its central finding is that local emissions account for 80 to 85 per cent of Delhi’s pollution. The policy consequence is a dual responsibility: regional cooperation is necessary for transported pollution and residue burning, while Delhi must continuously control the sources generated within its own urban boundary.
For residents, the distinction between local and external pollution does not change the immediate experience of poor air. It does, however, change the accountability question. When a large share of emissions originates from vehicles, industry, construction, domestic activity, waste burning and road conditions, improvement depends on the daily performance of public systems. The air-quality crisis is therefore also a test of transport management, construction regulation, waste services, industrial compliance and municipal maintenance.
The evidence supplied in the report confirms three broad points. First, Delhi’s pollution is substantially local according to the cited source-apportionment analysis. Second, vehicles are the largest identified local contributor, followed by industry. Third, the regulatory architecture covers many of the relevant sources but is criticised in the report for focusing mainly on winter conditions. What remains less clear from the supplied material is how consistently the existing directions are enforced throughout the year and how the new 500-by-500-metre emissions framework will alter operational decisions.
Those are the developments that deserve monitoring. The effectiveness of the PUC certificate fuel rule, enforcement of construction and industrial controls, the adoption of electric three-wheelers, the use of mechanical road-cleaning standards and the functioning of the new emissions inventory will determine whether Delhi’s response moves beyond seasonal crisis management. Until those systems operate continuously, the city’s air pollution will remain not only an environmental emergency but also a test of urban governance.
Urban Acres
Kolkata’s Ground-Level Ozone Falls, But Green Zones Still Struggle
Kolkata’s ground-level ozone readings improved sharply during the summer of 2026, but the city’s air-quality picture remains more complicated than a zero-violation count suggests. Data cited from a Centre for Science and Environment analysis show that ozone exceeded the national eight-hour standard on 46 days in 2021, fell to 22 days in 2025 and was not recorded above the standard on any day during the 2026 summer. Yet ozone remained elevated in several green areas, crossed the standard during parts of the winter and was substantially more persistent in neighbouring Howrah.
That contrast matters because ozone is not a single environmental problem with a single location or source. The protective ozone layer high in the atmosphere and ground-level ozone near the surface are chemically identical, but their effects and policy implications are different. The upper layer shields the Earth from harmful ultraviolet radiation. Ground-level ozone is an air pollutant that forms when nitrogen oxides, volatile organic compounds and other pollutants react in sunlight.
The distinction is particularly important for cities because ground-level ozone is not emitted directly in the same way as exhaust smoke or industrial fumes. It is produced through atmospheric chemistry. Vehicles and industrial activity can supply precursor pollutants, but the final concentration depends on sunlight, temperature, rainfall, cloud cover, wind and the movement of polluted air across municipal boundaries. A reading at one monitoring station therefore reflects both local emissions and wider atmospheric conditions.
The CSE figures indicate a clear summer improvement in Kolkata. The number of days on which the eight-hour national ozone standard of 100 micrograms per cubic metre was exceeded declined from 46 in 2021 to 22 in 2025. During the summer of 2026, no such exceedance was reported in the city. That is a meaningful change in the monitoring record, but it does not establish that the underlying sources of ozone precursors have been eliminated or that the improvement will persist across seasons.
The seasonal pattern in the same report points to that limitation. Between November 2025 and January 2026, ozone exceeded the prescribed standard on 12 days. This suggests that a summer reading cannot by itself describe Kolkata’s annual exposure pattern. Ozone formation is shaped by a combination of emissions and atmospheric conditions, and the relationship between these variables can change across seasons.
The location of the exceedances also complicates the assumption that parks and tree-covered areas automatically provide protection from every form of air pollution. Between March and May 2025, Rabindra Sarovar recorded ozone above the standard on 17 days. Jadavpur recorded five such days, Rabindra Bharati University three and Victoria Memorial two. By contrast, no comparable exceedances were recorded at Ballygunge, Bidhannagar and Fort William during the period covered by the report.
These differences do not mean that green spaces cause ozone pollution. They show instead that ozone behaviour cannot be understood only through a simple distinction between polluted roads and clean parks. Ozone and its precursor pollutants can move through the urban atmosphere, and concentrations can be affected by local geography, sunlight, air circulation and the chemical reaction of pollutants over time. The supplied report does not establish why individual monitoring locations recorded different results, but the variation makes location-specific interpretation essential.
The comparison with Howrah is even more significant for understanding the wider metropolitan system. During the summer of 2025, ozone exceeded the standard on 58 of 92 monitored days in Howrah, compared with 22 days in Kolkata. Dasnagar alone recorded 57 days of exceedance. CSE also noted that the expansion of monitoring stations in Howrah may have influenced the observed trend. This qualification is important: an apparent increase can partly reflect better coverage rather than only a deterioration in air quality.
At the same time, the figures demonstrate why air pollution cannot be managed solely within Kolkata’s administrative boundary. Kolkata and Howrah form a connected urban region in which traffic, industrial activity, residential settlements and atmospheric movement do not stop at a municipal line. If precursor pollutants travel across that boundary, separate local responses may not fully explain or control the resulting ozone concentrations.
The health concern arises from the pollutant’s effect close to the ground. According to the report, experts have warned that ground-level ozone can affect the respiratory tract and lungs, with higher risks for children, older people and those who already have respiratory illnesses. The available material does not provide hospitalisation figures or a Kolkata-specific health assessment, so the data cannot be used to quantify the city’s health burden. It does, however, establish why exceedance days matter beyond an air-quality dashboard.
The policy challenge is therefore different from controlling a pollutant that can be traced directly to one visible source. Reducing ground-level ozone requires attention to nitrogen oxides, volatile organic compounds and other precursor pollutants, alongside monitoring of the weather and atmospheric conditions that help produce ozone. The supplied report does not identify a new government programme, enforcement action or emissions-reduction measure linked to the 2026 improvement. It also does not establish whether the reduction resulted mainly from lower emissions, favourable weather, rainfall, cloud cover, temperature changes or a combination of factors.
That uncertainty does not cancel the improvement, but it defines how it should be interpreted. A fall from 46 exceedance days in 2021 to none during the 2026 summer is a positive signal in Kolkata’s monitoring record. It is not yet evidence of a permanent reversal. To determine whether the trend represents structural improvement, authorities and researchers would need to examine longer time periods, seasonal variation, precursor emissions and the consistency of readings across monitoring locations. The report itself calls for closer study of weather, rainfall, cloud cover, temperature and atmospheric chemistry.
The monitoring network is central to that interpretation. Howrah’s experience shows how the number and location of stations can affect the picture available to the public. More stations can reveal pollution that earlier monitoring missed, but comparisons across years must account for changes in coverage. Without that context, a city may appear to have become more polluted simply because it has started measuring more intensively, or appear cleaner because problematic locations are not adequately represented.
Kolkata’s ozone paradox is therefore not that one part of the atmosphere is recovering while another is worsening. It is that two different ozone questions are being discussed at once, while the urban air-quality system is producing a mixed and geographically uneven record. The protective upper-atmosphere layer is a global environmental issue; ground-level ozone is a metropolitan governance and public-health issue shaped by emissions, weather, monitoring and regional movement of pollutants.
The evidence currently confirms three points: Kolkata recorded no ozone-standard exceedance during the 2026 summer; exceedances had already declined substantially from 2021 to 2025; and ozone remained a concern during the winter period, in selected green areas and across the Hooghly in parts of Howrah. What remains uncertain is whether the summer improvement reflects a durable change in emissions or a favourable combination of atmospheric conditions. That distinction will become clearer only through continued, seasonally consistent monitoring and analysis of the wider Kolkata–Howrah airshed.
