2-T oil or engine oil is used mainly by 2-stroke engine vehicles like autorickshaws and some two-wheelers as an additive. The Government has taken this step to prevent owners of these vehicles from using loose 2-T oil in excess of the required amount (2 per cent of the fuel) to save on petrol expenses.

Specifications for the oil have also been notified under the Environment Protection Act as the additive is most prone to adulteration and spurious oil is widely circulated in the market. Environmentalists feel the move will reduce vehicular pollution by nearly 10 per cent. Using more than the required quantity of loose 2-T oil increases the level of Suspended Particulate Matter (SPM) in the exhaust. The SPM in Delhi's atmosphere is already higher than the prescribed level.

2-T oil will now be mixed at the dealer stage and not the manufacturing stage as only select vehicles require it. All petrol outlets will have to install a special dispenser for this pre-mixed oil by the prescribed date. This was one of the recommendations of the Environment Protection Committee set up by the Supreme Court under the chairmanship of Bhure Lal in an attempt to control pollution in Delhi.