6 min readNov 3, 2026 05:53 PM IST First published on: Nov 3, 2026 at 05:52 PM ISTIt is heartening to note the seriousness with which authorities have planned a slew of measures under Delhi’s Winter Action Plan, which commenced on November 1. These include restrictions on the entry of Delhi vehicles that do not comply with BS-IV standards, the “No PUCC, No Fuel” policy and construction curbs. However, the first day of the Action Plan brought a dose of despair: The air turned “Very Poor” after a prolonged pause, reminding us that something vital is still missing. While authorities appear prepared to implement the Action Plan, experts must do more to ensure that it is firmly grounded in science.Two major concerns demand serious attention: An immediate shift towards airshed-based mitigation and a decisive move away from quick fixes and removing the illusion that GRAP, by itself, can deliver meaningful and sustained reductions in air pollution. I shall elaborate on these shortly.AdvertisementWeather vagaries are increasingly emerging as formidable factors that influence air quality under rapidly changing climate conditions. This year, the onset of Delhi’s peak pollution season has been delayed by almost two weeks, with Super El Niño potentially playing a leading role. Let us understand why. Cyclone Arnab and its associated unexpected rainfall further delayed its onset. At the heart of this unusual delay was a climatic tug-of-war between sluggish wind speeds and the delayed onset of a milder winter. While slow winds favour pollution accumulation, a delayed and milder winter tends to keep pollution levels relatively lower. Both phenomena are possible footprints of the unprecedented Super El Niño — they are consistent with recent NIAS research which demonstrates a strong connection between ENSO and air pollution. The delayed winter appears to have won the first round, keeping pollution in check and pushing back the onset of the poor air season.Also Read | Three air purifiers, one AQI monitor and no peace of mindPaddy harvesting in neighbouring Punjab and Haryana was also delayed because of the uncertainty caused by rainfall deficits. NASA’s MODIS sensors aboard Terra and Aqua may continue to miss many stubble-burning fires because the satellites pass over Punjab and Haryana at times when the fires are not yet burning or have already died down. This mismatch has become much more pronounced since 2023, making NASA fire counts increasingly unreliable. According to reliable reports, more than 90 per cent of stubble-burning events in Punjab during 2024 and 2025 occurred after 3 PM, compared with less than 3 per cent in 2021. South Korea’s Korea Multi-Purpose Satellite-2A (KOMPSAT-2A) is beginning to reveal a substantially different picture through its Advanced Meteorological Imager (AMI), which, being geostationary, maps areas continuously. It is detecting abundant agricultural fires in Punjab, with fire counts orders of magnitude higher than those indicated by official estimates. NIAS air-quality modelling further reinforces this concern. When realistic additional stubble-burning emissions are incorporated, the model reproduces the abrupt rise in measured PM2.5 levels observed on November 1, attributing approximately 20 per cent of Delhi’s PM2.5 burden to stubble burning. Such a magnitude of pollution cannot be adequately predicted using historical averages of recent years’ fire data or NASA’s conventional fire counts. After all, any model can deliver realistic predictions only when supplied with realistic real-world inputs. The sooner authorities recognise this changing ground reality and subscribe to appropriate satellite data, the sooner we can improve emissions estimates and air-quality forecasts. Proper diagnosis is the prerequisite for effective treatment, and air-pollution management is no exception.On the policy front, unless Delhi adopts an airshed-based approach, it would effectively address only 50–70 per cent of the emission sources impacting the city, even before accounting for the additional contribution from stubble burning. A recent NIAS study, undertaken under a project of the Office of the Principal Scientific Adviser to the Government of India, proposes a paradigm shift in India’s air-quality management through an indigenous framework, “AIRSHEDEM”. It demonstrates how airshed-based master planning can potentially bring mitigation planning closer to a near-100 per cent source coverage. This approach focuses on a pragmatic middle ground that is neither the entire NCR nor restricted to Delhi NCT. This could provide a scientifically sound and administratively feasible framework for effective mitigation. AdvertisementThe second issue is GRAP. I see a compelling clinical analogy here: GRAP is akin to an ICU intervention for a chronic patient. Emergency treatment is essential to stabilise the patient and provide immediate relief, but it cannot cure the underlying disease. It also comes at the cost of repeated public inconvenience. A science-based action plan requires focused, sustained treatment of the diagnosed causes. Similarly, GRAP’s emergency restrictions are necessary when pollution peaks, but they cannot substitute for structural, long-term emission reduction. That is the key.you may likeThe next 30–40 days are likely to be particularly challenging. Stubble burning, unstable early-winter meteorology and intermittent high-emission episodes could continue to haunt Delhi’s air quality. The prospect of these factors converging in the second week of November is high. The next two months may prove even more difficult as deeper winter brings local fog as well as fog carried into Delhi from the Indo-Gangetic Plain, potentially worsened by an ENSO-related decline in western disturbances — the weather systems that periodically bring rain and atmospheric relief. Combined with significantly slower winds, these conditions could leave Delhi’s atmosphere choked. Of course, year-round priorities must not be lost sight of amid the seasonal crisis. Traffic congestion at junctions, poorly maintained roads, ineffective traffic management and open waste burning remain persistent sources of pollution that demand sustained attention. Delhi needs to move beyond repeatedly managing pollution episodes towards addressing their underlying causes through comprehensive airshed-based planning, sustained emission reduction and science-based policy implementation.The writer is Chair Professor, National Institute of Advanced Studies, IISc Campus, and Founder Project Director, SAFAR