Kolkata's public transport has to move to CNG Metropolises in this country have made, or are in the process of making, a switch to CNG as far as their public transport system is concerned. The first, and most comprehensive, switch was made by Delhi, which converted all public transport vehicles ~ three-wheelers, taxis and buses ~ to CNG mode. As subsequent years showed, there was a dramatic improvement in air quality ~ that the gain is now being offset by the phenomenal explosion in the number of private vehicles is, of course, an entirely different matter. Bangalore and Mumbai did not take too long to learn the lesson Delhi offered and have been switching to CNG for public transport vehicles. But Kolkata refuses to think today what Delhi thought yesterday, largely because unions for some perverse, not to say inexplicable, reason refuse to sanction the shift to CNG ~ and the government defers to them. So, the proposal, mooted by the government itself, to convert two-stroke three-wheelers to CNG mode has been shelved. What is on offer instead is a proposal to retire them and replace them with four-stroke petrol/diesel vehicles. The whole thing is absurd. The government will shell out a subsidy for the replacement and vehicle owners will incur a hefty cost ~ a new four-stroke vehicle costs well over Rs 1 lakh, while converting to CNG cannot possibly cost more than a few thousand rupees. Moreover, CNG is much cheaper, which will bring down operating costs and leave bigger profit margins for the operators. So why are the unions so set against CNG? There could be a petrol/diesel lobby angle but it is difficult to tell. This much is certain ~ if Kolkata's poisonous air is to be cleaned up the CNG switch for the entire public transport system is essential. In Delhi it took a Supreme Court order and an intense campaign by public interest groups, especially the Centre for Science and Environment, to bring about the change. That is what is required in Kolkata as well. A public interest petition in either the Calcutta High Court or the Supreme Court is needed to break the back of perverse union resistance backed by the honourable state transport minister. Game, anyone.