Issue Date: Jan 15, 2011
THE Central Pollution Control Board (CPCB) has fumbled in answering a critical question on carbonyl and methane emissions from vehicle exhausts: which pollutes less—petrol, diesel, CNG or LPG? The pollution watchdog’s study on emissions provides a database that could be used to give a policy message. It declared CNG to be the worst fuel for four-wheeled light and heavy commercial vehicles. But the finding is flawed as it compared factory-fitted petrol and diesel engines with retro-fitted CNG and LPG engines to test the fuel. In retro-fitted vehicles, engine is installed at local workshops.