We've been hearing that hydrogen cars will be here "in five years" for about 20 years now. Hyundai wants us to think that they're actually here, so they put on a display to show just what it emits. And it's true, this car only squirts out water. The plants aren't dying!
Hyundai put the car with the hydrogen tech, which is totally a real and viable thing that will be on the roads ASAP, on a stand in London and ran it. They captured the water vapor, condensed it, and then sent it to the plants and fish they had so they could live and thrive.
Yes, this does show that hydrogen and fuel cell tech isn't fake and does actually work, but it doesn't solve the problem of a hydrogen infrastructure or the costs associated with a hydrogen drivetrain.
Cool experiment, just not totally ready for prime time yet.