A 55-seat bus powered by biogas, sourced from cow dung, was launched here on Friday. The operators claim it is India's first such bus service.A nominal fare of Re 1 will be charged from each passenger.The bus, to run on the 17.5 km Ultadanga-Garia stretch, will be one of the fleet of 16 buses to be deployed across Kolkata and surrounding areas."The bus gives a mileage of six km for one kg biogas that costs Rs 20," Jyoti Prakash Das, Chairman and Managing Director of Phoenix India Research and Development Group, an alternative energy company, told IANS.The vehicle is powered by a German technology engine.The initiative has been undertaken under a central subsidies plan of the Ministry of New and Renewable Energy.As many as five buses will be pressed into service in the city.