Pollution in east, north and central Indian cities primarily comes from residential and transportation sectors, while in western India, industry and energy are the main contributors to local PM2.5 pollution, a study has found. Published in the journal Modeling Earth Systems and Environment, the study also found that PM2.5 pollution in cities in south India majorly comes from the industry and residential sectors. Researchers from the Indian Institute of Tropical Meteorology, Maharashtra, and the Indian Institute of Technology Roorkee, analysed pollution levels in 53 cities, having more than a million population during the winter of 2015-2016. Residential emissions -- from burning biomass for cooking and heating -- were found to be the leading contributor to local PM2.5 pollution in Srinagar (68 per cent), Varanasi (37 per cent), Allahabad (34 per cent) and Kanpur (33 per cent). The transportation sector's contribution to local PM2.5 pollution was found to be higher in north Indian .