New Delhi: Delhi-NCR’s early-winter air pollution has worsened in 2026, with average fine particulate matter (PM2.5) levels even in the week before Diwali reaching a three-year high. Vehicular emissions and pollution flowing in from neighbouring districts continued to drive poor air quality, according to a new analysis by the Centre for Science and Environment (CSE).The analysis found that the average PM2.5 concentration during the week preceding Diwali stood at 236 micrograms per cubic metre (µg/m³), a 97% increase from 120 µg/m³ in 2025 and 32% higher than the 179 µg/m³ recorded in 2024.Pollution levels during the pre-winter period were generally higher this year than in 2025, except for a brief decline in late September due to rainfall, the analysis said.CSE said the findings pointed to inadequate year-round pollution control, with Diwali firecrackers and farm fires aggravating an already high pollution baseline rather than being the sole causes of the crisis.In a statement, Anumita Roychowdhury, executive director of research and advocacy at CSE, said,“Diwali pollution is an annual tipping point, but elevated particulate levels before the festival this year show that baseline pollution is higher than in previous years.” Roychowdhury also mentioned that inadequate emission control across major pollution sources had contributed to the worsening air quality.The analysis drew on air quality data from the Central Pollution Control Board (CPCB), pollution source estimates from the Indian Institute of Tropical Meteorology (IITM), crop-fire data from the Indian Agricultural Research Institute and traffic analytics from TomTom.Vehicles and regional pollution drive Delhi’s toxic airAccording to IITM’s Decision Support System data for November 1-8, pollution transported from neighbouring national capital region (NCR) districts accounted for more than 50% of Delhi’s PM2.5.Among Delhi’s local sources that also contributed to pollution during this time, vehicular transport was the largest contributor, accounting for 52% of pollution. Residential activities contributed 13%, followed by peripheral industries at 11%. Construction accounted for 7%, while energy use and waste burning contributed 5% each, the CSE analysis said.Stubble burning accounted for 3.9% of Delhi’s PM2.5 during the enforcement of Graded Response Action Plan (GRAP) Stage I. Its contribution rose to 11.5% on November 1 and 8.6% on November 2, before reaching a seasonal peak of 16.2% on November 4.By November 6, when GRAP Stage III restrictions were invoked, the contribution had fallen to around 8%, but Delhi’s Air Quality Index (AQI) had deteriorated to 382.The analysis said severe pollution persisted even as the contribution from farm fires declined, highlighting the role of local and regional emissions.New pollution hotspots emerge across DelhiThe analysis also identified high pollution levels in several areas beyond Delhi’s 13 officially designated pollution hotspots.Between October 1 and November 8, 11 of the 13 designated hotspots recorded lower PM2.5 concentrations than during the corresponding period in 2025. Anand Vihar saw a 49% decline, followed by Wazirpur at 41%, Ashok Vihar at 40% and Bawana at 22%.However, Jahangirpuri and Punjabi Bagh recorded marginal increases of 2% and 1%, respectively. Jahangirpuri remained the most polluted designated hotspot, with an average PM2.5 concentration of 163 µg/m³.Several areas not officially classified as hotspots also recorded high pollution levels. Vivek Vihar had an average PM2.5 concentration of 144 µg/m³, followed by Sonia Vihar at 139 µg/m³, ITO at 137 µg/m³ and Delhi Technological University at 135 µg/m³.The CSE analysis also found that pollution had spread across NCR, with PM2.5 levels rising sharply in early November in Gurugram, Faridabad, Noida, Ghaziabad and Greater Noida.Emergency traffic curbs did little to ease congestionsThe analysis found that emergency traffic restrictions under GRAP had provided little relief from weekday congestion in Delhi.Between November 2 and 6, the city recorded an average daily Travel Time Index (TTI) of 2.40 and an evening peak of 3.49. Both figures were virtually unchanged from October 30, just before the restrictions took effect, when the daily TTI stood at 2.38 and the evening peak at 3.48.Commuters continued to take 13% longer to complete their journeys than on standard weekdays between January and April 2026, according to the analysis.In a statement, Shubham Srivastava, deputy programme manager for clean air and sustainable mobility at CSE, said the restrictions had failed to significantly reduce weekday traffic congestion.The analysis also examined nitrogen dioxide (NO2), a marker of vehicular pollution. Nearly 80% of NO2 emissions come from vehicles, according to the CSE report.NO2 levels rose sharply during the evening rush hour and remained elevated until midnight, even after the evening rush had subsided. Daily NO2 concentrations increased by around one-third from November 2, while congestion remained largely unchanged.“In effect, the evening rush loads the air and the still night air keeps it there,” said Sharanjeet Kaur, deputy programme manager at CSE’s Urban Lab.CSE calls for year-round pollution controlCSE said the emergence of new pollution hotspots and the deterioration in air quality across the NCR pointed to persistently high baseline emissions.Roychowdhury said episodic spikes from firecrackers and farm fires were aggravating the problem, but the region’s pollution crisis was rooted in inadequate year-round action across major sectors.She said emergency measures could not substitute for sustained emission reductions across transport, industry, construction, waste burning and other urban sources.Srivastava said traffic congestion itself worsened pollution, as vehicles emit more per kilometre when idling or moving slowly.He called for measures to reduce the number of vehicles on roads, including expanded mass public transport, trip-reduction measures and stricter restrictions on private vehicles.“Conventional traffic engineering and piecemeal emergency restrictions cannot absorb this overload,” he said, adding that effective pollution control required strategies to actively reduce vehicular traffic across the city.