Hydrogen fuel cells
It is true that this technology is still to mature, but major automobile manufacturers around the world are pushing for fuel cell cars quite seriously. Europe, Canada, Japan and Korea are readying to have fuel cell vehicles on their roads. Fuel cells have the biggest advantage of near zero emission.
On the other hand, our country does not have even a single world class research facility for the same. I hope that Modi government puts some impetus on the same. more