Indoor air pollution from coal burning is a known human carcinogen (IARC group 1), while that from biomass (primarily wood burning) is a probablehuman carcinogen (IARC group 2A). It contains many hazardous pollutants including known human carcinogens such as benzo(a)pyrene, formaldehyde
and benzene.Exposure to such indoor air pollution is a major public health concern in India because the majority of its population still relies on solid fuels for cooking.