A groundbreaking satellite-based assessment has delivered a sobering verdict: Delhi stands as the most polluted among all Indian states and Union territories. The comprehensive study, conducted by the Centre for Research on Energy and Clean Air (CREA), exposes the capital's severe air quality crisis that far exceeds national and international safety standards.
Alarming Pollution Levels in the Capital
The research reveals that Delhi recorded an annual population-weighted PM2.5 concentration of 101 micrograms per cubic meter. This staggering figure represents 2.5 times higher than India's national ambient air quality standard and an astonishing 20 times the World Health Organization's recommended guideline. The assessment methodology focused on population-weighted PM2.5 levels, which accurately reflects actual human exposure to dangerous particulate matter rather than just ambient air pollution readings.
The Airshed Crisis: Beyond City Boundaries
The study identifies that the Indo-Gangetic airshed, which includes Delhi, continues to bear the highest pollution burden nationwide. An airshed refers to a geographical region sharing common air quality due to similar weather patterns and topography that trap and circulate pollutants across the area. According to CREA analyst Manoj Kumar, India's airshed configuration varies seasonally, ranging from nine to eleven distinct airsheds throughout the year.
Traditionally cleaner regions are now showing concerning trends. The Assam-Tripura airshed has emerged as the second-most polluted area after the Indo-Gangetic plains, indicating that air quality issues are spreading beyond their traditional boundaries. Together, Delhi and Assam account for nearly half of India's 50 most polluted districts, with Haryana and Bihar also featuring prominently in this distressing ranking.
National Crisis: Widespread Pollution Across Seasons
The assessment paints a grim picture of nationwide air quality deterioration. Across India, 447 out of 749 districts breach the annual PM2.5 limit, demonstrating that dangerous pollution levels have become a persistent, year-round national crisis rather than being confined to major cities or winter months.
The study documents clear seasonal patterns: pollution peaks during winter, affecting 82% of all districts, temporarily drops during monsoon season, and surges again post-monsoon. This cyclical pattern underscores that meteorological conditions provide only temporary relief while baseline emissions remain the core problem requiring urgent addressing.
The research emphasizes the critical need to transition from city-based air quality planning to a comprehensive airshed-based governance framework. This approach recognizes how pollution travels across district and state borders, necessitating coordinated regional strategies rather than isolated local interventions. Kumar also revealed plans to soon release daily satellite-derived PM2.5 maps, providing more timely data for policymakers and the public.
