The case emerged from a public interest litigation initiated by environmental activist M.C. Mehta regarding air pollution in India and the enforcement of Bharat Stage (BS) emission standards for vehicles. ... The Supreme Court had previously banned the sale and registration of BS-III vehicles from April 1, 2017, and the current proceedings examined the permissibility of continuing BS-IV vehicle sales post-March 31, 2020, amidst a backdrop of advocating for stricter BS-VI norms, with the Society of Indian Automobile Manufacturers (SIAM) seeking an extension against opposition from environmental and public health proponents.