End of winter report 2023-24: Spread and scale of air pollution crisis in India

Toxic air pollution came back to trouble the public yet again this winter. The air quality this winter started to worsen much earlier than usual  due to low rains in September- October and  was made even worse due to low wind speed through the season. But air quality is not a monolith, especially in India where regional variations are significant. This report of Urban Lab of Centre for Science and Environment provides a comprehensive nationwide review of winter air quality. The objective of the study has been to deepen the understanding of local and regional status, variation and trend of the winter pollution. This is part of the fourth edition of Urban Lab’s Air Quality Tracker Initiative which was started in 2020 to study the impact of pandemic lockdowns on air quality of Delhi and NCR.

This concluding report on the 2023-24 winter air pollution reveals that North and East India remain the most polluted regions of India. Air quality in North India was significantly worse this winter compared to the previous winter. Meanwhile, significant improvement was noted in East India’s winter air. South India continues to have the lowest regional PM2.5. Overall, even though there is considerable variation in regional averages, high pollution episodes are common across regions. Improved realtime monitoring has strengthened the evidence that PM pollution is a regional scale problem as it is again observed that the rise and fall in PM levels is highly synchronised within regions despite large distances.