Delhi Air Pollution — Definition
Definition
Delhi air pollution refers to the contamination of atmospheric air in the National Capital Territory of Delhi by harmful substances including particulate matter (PM2.5 and PM10), nitrogen oxides, sulfur dioxide, carbon monoxide, and ozone.
This pollution manifests as visible smog, particularly during winter months, creating hazardous breathing conditions. The Air Quality Index (AQI) measures pollution levels on a scale of 0-500, with Delhi frequently recording 'Poor' (201-300), 'Very Poor' (301-400), and 'Severe' (401-500) categories.
PM2.5 particles, smaller than 2.5 micrometers, are particularly dangerous as they penetrate deep into lungs and bloodstream. Delhi's annual PM2.5 average consistently exceeds WHO guidelines of 5 μg/m³ and Indian standards of 40 μg/m³, often reaching 80-120 μg/m³.
The crisis intensifies during October-February due to meteorological factors like temperature inversion, reduced wind speeds, and additional pollution sources including stubble burning in neighboring states.
From a UPSC perspective, this topic integrates environmental science, public policy, federalism, and judicial activism, making it crucial for both Prelims factual questions and Mains analytical answers on governance, health policy, and sustainable development.