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 and the current proceedings examined the permissibility of continuing BS-IV vehicle sales post-March 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