The bus is operated using an electro-chemical engine working under reverse electrolysis process, V Gnana Gandhi, the brain behind the project, said while explaining the use of liquid hydrogen to propel automobiles. Hydrogen compressed to 150 bar atmosphere is stored in cylinders on the roof of the bus. The fuel reaching the engine is decompressed to 2 bar atmosphere and thereafter converted by the hydrogen fuel cells into direct current (DC). This power is then converted into alternate current (AC) to drive the electric engines. “This is basically an electric operation using hydrogen fuel. As the by-product is water, absolutely there is no emission at all,” Gandhi stated.