What factors contributed to the air pollution in Delhi as described?

• A. A single industrial emission event
• B. A mix of weather conditions, urban emissions, and rural smoke converging over the capital region
• C. Only vehicle emissions
• D. A natural wildfire plume from nearby regions

Answer: (B)

Air quality episodes in Delhi are driven by a combination of sources and atmospheric conditions, not a single cause. The best choice captures how weather patterns that limit dispersion (like calm winds, temperature inversions, and a shallow mixing layer) allow pollutants to build up, while urban emissions from vehicles, industry, and construction add large amounts of primary pollutants. At the same time, smoke from biomass burning in surrounding rural areas is carried toward the capital by regional winds. When these three inputs converge over the region, pollutant concentrations rise dramatically, especially in winter when stagnation is common. This integrated view explains why Delhi’s pollution spikes are tied to both local emissions and regional burning, modulated by weather, rather than to any one source alone.