The Delhi government has initiated a project to run the entire public transport on "eco friendly" fuel. Sources said the project will be implemented in a phased manner and most public transport will switch over to eco-friendly fuels, primarily compressed natural gas (CNG) and propane. While the transport ministry has started procuring CNG buses for the DTC, the ministry is exploring the possibility of replacing all TSRs, taxis and even maxi-cabs, that now run on petrol or diesel. Sources in the ministry said three options were available for TSRs. CNG and propane have been found suitable for converted TSRs.