PENNY WICE Sarath Chelluri / Mumbai October 13, 2008, 0:39 IST The rising demand for CNG and PNG as cleaner and cost efficient fuels, and the Commonwealth Games are positive triggers for Indraprastha Gas. Indraprastha (old name of Delhi) has seen a lot battles, but in the modern times, a different type of battle is being waged by Delhi citizens. Since the last decade, Delhi-ites have been fighting hard against pollution. Delhi was regarded as one of the world