Context: Changing pollution discourse: Scientific evidence increasingly recognises that Delhi’s air pollution cannot be addressed through city-level measures alone; pollution sources across the wider region must also be tackled.
- Transport emissions: A study by the System of Air Quality and Weather Forecasting and Research (SAFAR), under the Ministry of Earth Sciences (MoES), identified transport as a major contributor to Delhi’s toxic pollution, accounting for around 40% of PM2.5 emissions in the reported assessment.
- Policy imbalance: The National Clean Air Programme (NCAP) has linked funding and performance assessment largely to reductions in PM10, potentially diverting attention from PM2.5, which poses greater health risks.
How a Strong El Niño Could Worsen Delhi’s Winter Pollution
- El Niño: A climate phenomenon involving abnormal warming of the central and eastern equatorial Pacific Ocean that can alter atmospheric circulation and India's monsoon.
- Weaker monsoon and rainfall deficit: The article notes that the preceding super El Niño affected India's monsoon, which ended with a 13% rainfall deficit, the highest in a decade, although Delhi recorded a 17% surplus.
- Reduced wind speed: Strong El Niño conditions may weaken winds over North India, limiting the dispersion of pollutants.
- Reduced western disturbances: These weather systems bring winter precipitation to northern India. Their likely near-absence under severe El Niño conditions could remove an important mechanism for periodically washing pollutants out of the atmosphere.
- Temperature inversion: Milder daytime temperatures combined with stagnant, cooler nighttime conditions may lower the surface inversion layer, trapping pollutants close to the ground and sharply increasing their concentration.
Climate Change and Stubble Burning
- Punjab and Haryana rainfall deficits: The article reports monsoon rainfall deficits of around 23–40% in some places. Early monsoon rains nevertheless enabled early paddy sowing in some areas, potentially allowing harvesting to begin in early October.
- Shift in burning timings: Farmer interactions cited in the article suggest that stubble burning has shifted from morning to evening, meaning MODIS-based fire detection may miss a significant share of incidents.
- Winter pollution peak: Stubble burning typically peaks in early November, when winter conditions are already established. Without affordable alternatives, farmers may continue to rely on burning for rapid field clearance.
- Uncertain agricultural impact: The effect of rainfall deficits on rice production and, consequently, stubble burning remains to be established.
Why a City-Centric Approach Is Insufficient
- Regional pollution transport: Delhi's air quality is influenced by emissions from transport, industries, biomass burning and other sources across the Indo-Gangetic Region, alongside local emissions.
- Pollution trapping: Weak winds, reduced atmospheric mixing and unfavourable weather conditions can prevent pollutants from dispersing, allowing emissions from multiple sources to accumulate.
- Extreme weather interaction: Climate change can intensify natural drivers of pollution, compounding the effects of human-generated emissions and making air-quality management more complex.
Way Forward: Airshed-Based Pollution Management
- Airshed approach: An airshed is a geographical region within which air pollutants move and interact across administrative boundaries. Managing emissions across the entire airshed is more effective than focusing on individual cities in isolation.
- Satellite-based monitoring: The National Air Quality Resource Framework of India (NARFI), developed by the National Institute of Advanced Studies (NIAS) under the Office of the Principal Scientific Adviser, outlines an airshed-based framework; satellite-defined airsheds could offer a practical operational alternative where comprehensive regional implementation is difficult.
- Integrated action: Coordinate emission reduction across States and sectors, including transport, industries, power generation, construction dust and agricultural residue burning.
- Evidence-based policy: Improve scientific forecasting, satellite fire detection and source-apportionment studies to identify changing pollution patterns and guide targeted interventions.
- Short-, medium- and long-term measures: Combine immediate winter pollution controls with sustained regional emission reductions, cleaner technologies, residue-management alternatives and institutional coordination.
