It was way back in 2001 when the first steps to curb pollution emerging from vehicles in Delhi was taken. The Supreme Court set March 31, 2001, as the deadline for Delhi to transition from petrol autos and diesel-run buses to compressed natural gas (CNG). In the 1998 verdict, the court noted that vehicular pollution contributed 70 per cent to air pollution then, compared to 20 per cent in 1970 and ordered immediate actions to “arrest the growing pollution of air”.