Taxi operators prefer diesel over LPG to run their vehicles. A Telegraph picture

January 2006: The pollution level in Calcutta is very high. The best thing I can do for the city is play a part in cleaning its air — Raja Mukherjee of Bijoygarh, after buying a liquefied petroleum gas (LPG)-run taxi.

February 2007: I can no longer maintain my green taxi after incurring losses for over a year — Mukherjee, after spending Rs 48,000 to fit a diesel engine to the taxi.

Taxi-owners in the city are making their verdict clear, even as the state government and environmental experts argue over the cheaper option — diesel or LPG — for cabs.

Additional chief secretary of the state transport department Sumantra Chowdhury maintains that it is cheaper to operate diesel taxis than LPG taxis, but technical experts say it is so only for an Ambassador.

“LPG is cheaper than diesel by Rs 5 a litre, but diesel vehicles provide better mileage,” stated Chowdhury. “The non-availability of LPG round-the-clock is another hurdle.”

Petrol-run Ambassador engines can be converted to LPG engines, but diesel engines cannot be converted to LPG.

“An LPG engine gives the same mileage as a petrol engine. An Ambassador runs eight km per litre of petrol and 14 km per litre of diesel. While LPG costs Rs 28 per litre, diesel is priced at Rs 33 per litre,” explained Chowdhury.

Automobile expert and member of Calcutta Green Network S.M. Ghosh alleged that the government’s stand reflected its interest in promoting Hindustan Motors.

“LPG vehicles are less polluting and preferred all over the world. The state government should look to promote the use LPG to clean the city air,” he pointed out.

Ghosh elaborated: “In New Delhi, Maruti vans are permitted to be used as commercial vehicles. Tata Indicas, too, have been given permits for commercial use. Both cars provide mileage on a par with diesel vehicles and much better than petrol ones. The cars also cost less than Ambassador taxis. If we take maintenance cost into account, LPG taxis prove a better bet than diesel cabs.”