Yugcharan News / 12-11-2026
Delhi’s air pollution levels during the early winter period of 2026 have reached their highest point in three years, with the average concentration of fine particulate matter (PM2.5) in the week preceding Deepavali recording a significant rise compared with the previous two years. A new analysis by the Centre for Science and Environment (CSE), released on Wednesday, November 11, has highlighted the worsening pollution situation and raised concerns over the effectiveness of emergency measures introduced to control emissions and traffic congestion in the national capital.
According to the CSE assessment, the average PM2.5 concentration in Delhi during the week before Deepavali stood at 236 micrograms per cubic metre. This was substantially higher than the corresponding average of 120 micrograms per cubic metre in 2025 and 179 micrograms per cubic metre in 2024.
The figures represent a 97% increase compared with 2025 and a 32% rise over 2024, indicating that Delhi entered the festive period with a significantly higher pollution burden than in the preceding two years.
The findings are particularly significant because the deterioration continued even as the contribution of stubble burning to the city’s pollution declined during certain periods. The analysis points towards local emission sources, especially vehicular transport, as major factors behind the persistent deterioration in air quality.
The CSE also found that emergency traffic restrictions introduced by the authorities had not substantially reduced congestion. Evening traffic gridlocks continued to trap nitrogen dioxide (NO2), a pollutant associated with vehicle emissions, until midnight, extending the period during which residents remained exposed to traffic-related pollution.
PM2.5 Levels Rise Sharply Before Deepavali
The CSE analysis identified a considerable increase in particulate pollution in the days leading up to Deepavali. The average PM2.5 concentration of 236 micrograms per cubic metre during the preceding week was the highest recorded for the comparable period in three years.
PM2.5 refers to fine particles with a diameter of 2.5 micrometres or less. These particles can remain suspended in the air and penetrate deep into the respiratory system, making them a significant concern during periods of severe air pollution.
The increase in Delhi’s pre-festival pollution levels suggests that the city was already experiencing a high baseline concentration of particulate matter before additional seasonal and festive emission sources could influence air quality.
The CSE said its findings were based on an examination of multiple datasets rather than a single pollution measurement. These included air quality information available through the Central Pollution Control Board (CPCB) portal, hourly estimates of pollution-source contributions from the Indian Institute of Tropical Meteorology (IITM), crop-fire data from the Indian Agricultural Research Institute (IARI), and traffic-related information.
By combining these datasets, the organisation assessed how different sources contributed to Delhi’s pollution during the period under review.
CSE Warns of Higher Baseline Pollution
Anumita Roychowdhury, Executive Director of Research and Advocacy at the CSE, described Deepavali pollution as an annual tipping point but said the elevated particulate levels before the festival this year indicated that the city's baseline pollution was already higher than in previous years.
She emphasised that emission-control measures need to operate throughout the year rather than being concentrated around the winter pollution season.
According to Roychowdhury, cleaner air conditions before the arrival of winter could help reduce the severity of seasonal pollution episodes. She said that if year-round emissions were controlled and temporary spikes caused by farm fires and firecrackers were kept in check, seasonal weather changes would not have triggered pollution levels of the same severity.
Her observations underline the importance of addressing pollution sources across different sectors throughout the year. Measures introduced only after air quality deteriorates may not be sufficient to prevent severe episodes if emissions have already accumulated at high levels.
Stubble Burning Contribution Declines, but Smog Continues
One of the major findings of the CSE assessment was that severe smog continued even when the contribution of agricultural residue burning declined.
Stubble burning in neighbouring agricultural regions is a recurring concern during Delhi’s winter pollution season. Smoke from crop-residue fires can travel towards the national capital and contribute to elevated particulate matter concentrations. However, the latest analysis indicates that farm fires were not the only factor behind the pollution levels recorded during the period.
According to the CSE, the contribution of stubble burning to Delhi’s citywide PM2.5 concentration stood at 3.9% during the enforcement of Stage I of the Graded Response Action Plan (GRAP).
The contribution subsequently increased to 11.5% on November 1, ahead of the invocation of GRAP Stage II. It then declined to 8.6% on November 2.
Farm-fire smoke reached a seasonal high of 16.2% on November 4, according to the organisation.
However, the CSE highlighted that by November 6, when GRAP Stage III was triggered, Delhi’s Air Quality Index (AQI) had deteriorated to 382 even though the contribution from stubble burning had fallen to approximately 8%.
The organisation said this indicated that severe pollution episodes could continue even when the contribution of farm fires declined, with local emissions remaining an important factor.
Delhi’s Local Pollution Sources: Vehicles Account for 52%
Vehicular transport emerged as the largest contributor among Delhi’s local pollution sources, according to the CSE analysis.
Data from IITM’s Decision Support System for November 1 to November 8 showed that pollution transported from neighbouring National Capital Region (NCR) districts accounted for 54.43% of Delhi’s PM2.5 concentration.
Local sources contributed 33.06%, while stubble burning accounted for 14.29%, the analysis stated.
Within Delhi’s local pollution sources, vehicular transport was responsible for 52% of the contribution. This placed it significantly ahead of other identified local sectors.
Residential activities accounted for 13% of local pollution, while industries located on Delhi’s periphery contributed 11%.
Construction activities were responsible for 7%, while energy use and waste burning each contributed 5%. Road dust and other sources accounted for 4% each, according to the CSE statement.
The figures highlight the importance of controlling emissions from vehicles and other urban activities alongside efforts to reduce pollution transported from outside the capital.
Traffic Restrictions Fail to Significantly Reduce Congestion
The CSE analysis also raised questions about the effectiveness of emergency restrictions imposed on vehicles during periods of worsening air quality.
The organisation said restrictions barring vehicles below the BS-VI emission standard had failed to reduce traffic volumes significantly.
According to Roychowdhury, traffic congestion analysis showed that vehicular emissions continued to contribute substantially to daily exposure to pollution. Evening traffic gridlock was particularly concerning because it allowed nitrogen dioxide concentrations, associated with vehicle emissions, to remain elevated until midnight.
Nitrogen dioxide is an important marker of traffic-related pollution. Its presence in congested urban areas reflects the impact of vehicle emissions, particularly where large numbers of vehicles remain on roads for extended periods.
The findings suggest that restrictions on specific categories of vehicles may not be sufficient on their own to address the broader problem of traffic-related emissions. Congestion management and sustained reductions in vehicle pollution remain important components of the overall response.
GRAP Measures and the Challenge of Winter Pollution
The deterioration in Delhi’s air quality during late October and early November coincided with the implementation of different stages of the Graded Response Action Plan.
The AQI entered the 'very poor' category on November 2. By November 6, it had reached 382, prompting the activation of GRAP Stage III, according to the CSE analysis.
GRAP is a set of emergency measures introduced to respond to deteriorating air quality in Delhi-NCR. Its different stages involve restrictions and pollution-control steps that become progressively more stringent as air quality worsens.
However, the CSE findings indicate that emergency restrictions must be supported by long-term emission-control measures. The continued presence of severe smog despite a decline in the contribution of stubble burning highlights the need to address pollution generated within the city and transported from neighbouring districts.
The organisation's analysis also points to the importance of improving the effectiveness of traffic-related interventions, particularly during evening hours when congestion can prolong exposure to harmful pollutants.
Multiple Sources Contribute to Delhi’s Pollution Crisis
The CSE assessment presents Delhi’s winter pollution as a combination of emissions from several sources rather than a problem that can be attributed to a single activity.
Pollution transported from neighbouring NCR districts accounted for the largest share of the PM2.5 contribution in the IITM data for November 1-8. Local emissions formed another substantial component, with transport dominating the identified sources within the capital.
Stubble burning also contributed during the period, with its share varying across different dates. However, the analysis shows that a reduction in farm-fire smoke did not automatically result in a corresponding improvement in overall air quality.
The findings underline the need for coordinated action involving transport management, industrial emission controls, construction-related dust reduction, waste-burning prevention and measures addressing pollution from surrounding regions.
With Delhi entering the winter season amid elevated particulate levels, the CSE analysis raises concerns about the city's preparedness to manage recurring pollution episodes. It also suggests that short-term restrictions introduced during severe pollution periods need to be complemented by consistent emission-reduction efforts throughout the year.
The central message emerging from the assessment is that Delhi’s air pollution cannot be controlled by focusing exclusively on stubble burning or imposing temporary traffic restrictions. The high pre-Deepavali PM2.5 average, continued congestion and significant contribution of vehicular emissions indicate that a broader, year-round strategy will be necessary to address the capital’s deteriorating air quality.
