A draft report prepared by the Indian Institute of Technology-Kanpur, sponsored by the Delhi government and the Delhi Pollution Control Committee, reveals the extent to which various sources contribute to air pollution in the city. The study identifies and classifies sources of pollution such as industry, traffic, power plants and small-scale industries for the period from November 2013 to June 2014. Vehicles emerged as an important contributor to pollutants in the city, along with road dust and industries. Among vehicles, trucks, buses and two-wheelers were the worst contributors to air pollution, above passenger cars.