India, Dec. 29 -- The rabbit is out of the hat. The cat is out of the bag, or rather set between the pigeons. Despite the cracking noises of Diwali crackers, crackling lights of farm fires, and flying dusts of creaking construction, vehicles are majorly responsible for the acute air pollution across Indian cities. Recently, the road transport and highways minister, Nitin Gadkari, publicly admitted that the transport sector contributes significantly to pollution, and stressed the urgent need to reduce the dependence on fossil fuels.

"I stay in Delhi for two days, and develop a throat infection," he said, and added that 40 per cent of air pollution is linked to his ministry. Incidentally, experts have linked pollution to the number of vehi...