Alternatives like CNG have, however, received some attention and GAIL, after an initial lethargy in setting up CNG filling stations in Delhi and Mumbai, has finally waken up and increased the number of outlets recently. These facilities are still woefully inadequate and, combined with the more than Rs 40,000 conversion cost, has found few takers, except government cars.

Another alternative that remains largely unknown, but is rapidly gaining ground, is running cars on LPG. Understandably, the government has been reluctant to encourage LPG conversions as there was a shortage of LPG in the country. But that argument lost its ground after LPG started being available on demandfrom private vendors. Today, there is virtually no waiting period to get a gas cylinder, especially from private companies who are doing roaring business even in cities other than the metros.

The kits for running cars on LPG have been available in India for quite some years now. But both sellers and customers of these kits are in favour of keeping the thing as quiet as possible as government policy on this issue is unclear and no NOCs (no objection certificates) are forthcoming from either the transport authorities or the petroleum ministry.

There are many advantages to running vehicles on LPG. Apart from the main advantage of virtually no emissions, running cars on gas is more economical in other ways. They include lower cost for lubricating oil as it lasts longer (no longer being diluted with petrol) and increase in engine life in the absence of carbon deposits. Unlike diesel and CNG conversions, no modification to the engine is required. Only specific additional equipment is installed.

The vaporiseris at the heart of the conversion kit. This instrument essentially reduces the pressure of the LPG, converting the gas into liquid, which is then passed directly into the carburettor. The other two important elements in the kit are the two solenoid valves that regulate the flow of gas or petrol. These are electromagnetic devices that in the case of a petrol solenoid valve, stops the flow of petrol when the car is being run on LPG. The LPG solenoid does the same when petrol is being used. It also stops flow when the engine is stopped.

Another advantage is that the converted cars can run on dual mode. Using LPG or petrol then becomes an optional choice for the consumer. On the flip side, however, it does provide 10 per cent lower power, which translates into a 3 per cent loss in maximum speed.

The cost of conversion in case of imported kits varies from Rs 7,000 to Rs 11,000. Locally made kits are available at as low as Rs 5,000. In India, there are at least 10 vendors who have been regularly importing andselling LPG conversion kits. In fact, according to sellers, the rate of conversion has increased exponentially in the past one year or so as kits of local manufacture have flooded the market.

Says R P Gupta, who has been selling Russian-made LPG conversion kits since 1995: ``The extremely low cost of conversion is driving the conversions. Also, fuel costs are reduced by more than half if cars are run on LPG.''The burgeoning business is, however, conducted in a most surreptitious manner. The government's fuzzy stand on this issue is responsible for this. Sellers justify their business on the ground that LPG is in any case freely available in the market. The economics of conversion and running costs are dramatically lower. Therefore, they say, the growth of the market is assured. It remains to be seen whether the government intends to regulate this market in any way.