The metro cities to begin with - and Delhi is on top of the list - may soon have commercially sustainable and low-on-emission hydrogen fuel cell buses plying on city roads. The buses are likely to become an integral part of the urban mass transit system in the country under the Global Environment facility-funded project on climate change. Worth $350,000, the full project proposal is in its final stage of preparation by UNDP, one of the three implementing agencies of GEF.The exercise to develop a full project proposal to demonstrate and facilitate the introduction of hydrogen fuel cell buses in the Indian transport sector is likely to be completed within a year.