TheAirCar.com is the information page for a compressed air powered car developed by Guy Nègre. It has the potential to be a truly emissions free vehicle as the only thing that would leave it would be what was originally put in, air. The car also features other environmental features, the body construction will not use sheet steel as most modern vehicles do but fiber-glass (or even hemp) instead. Something like this could help alleviate countless social troubles, pollution and fossil-fuel dependence for instance. Though the project has so far been vaporware, the ideas are sound and production negotiations are underway with Indian manufacturing group Tata Motors.

http://www.theaircar.com/