DTC is the largest CNG-powered bus service operator in the world with a fleet size of 3762 buses at present and is also in the process for procurement of 1000 new CNG buses which would shortly be plying on the roads of the national capital. DTC consumes around 2.80 lacs kgs of CNG per day for its buses which constitutes around 11% of daily CNG sale of IGL. The consumption of CNG is expected to increase further after the addition of new buses.

Earlier in 2010, IGL had signed the long term Gas Supply Agreement with OTC to supply CNG. As a part of the agreement, dedicated CNG filling facilities have been set up at 44 depots of DTC across Delhi and Naida to cater the fleet of DTC buses being used for public transport with a total compression capacity of 10 lakh kgs per day. These state of the art CNG filling facilities have helped in timely CNG fueling of the fleet. The initiative has resulted in optimization of time, finances and resources for OTC apart from ensuring timely commute of the buses on their respective routes. In addition, DTC has provided 19 plots adjacent to its depots to IGL for creation of hybrid facilities, which are used as retail outlets for serving the public