The two-wheeler industry is estimated to have incurred a loss of Rs 600 crore due to the three-day discount offered to customers after the Supreme Court ordered a ban on sale of BS-III vehicles, a report said. The major chunk of the loss is expected to be borne by the Original Equipment Makers (OEMS) even as retro-fitment of the unsold vehicles to make them BS IV-compliant is also an alternative, the report by ratings firm Icra said. The apex court on March 29 banned the sale and registration of BS-III category vehicles or those not compliant with Bharat Stage IV (BS IV) emission norms from April 1. The step was taken due to concerns on vehicular emission. The BS norms are emission standards imposed on automobile manufacturers which specify the maximum permissible limits for pollutants in the exhaust fumes of automobiles.