Yes, Mumbai has money. More money that I have seen anywhere else outside New York City. I have been to shops where the prices painfully high by US standards. I would not be able to afford life here any better than I can afford life in Santa Barbara. In fact, I think my standard of living would decrease on my same salary. And by the way, I have not seen an autorickshaw with that many people on it here.
But back to the energy efficient motor vehicles...Gasoline costs equivalent to $8 a gallon here. That is a lot by my standards. So there's an incentive for other fuels. And these other fuels work. You can stand next to traffic in hopeless traffic jams and you do not choke on exhaust. There isn't any exhaust to choke on unless a bus goes by. I suspect most of the pollution is from burning plastic and trash in the street.
I'm just saying that they've got a whole city here running on clean burning cars and other vehicles. And these cars can go plenty fast (if only there wasn't so much traffic). But the US auto industry wails and moans that it just isn't possible to do. That we don't have the technology. Considering that most people I know sit in terrible traffic idling or stopping and going at 11mph, I can't understand how it just isn't possible to have clean burning cars here. Makes no sense.