Except there's not enough known, proven lithium reserves on the planet to make enough cars to help with the air pollution there. That is, assuming that the pollution is mostly from cars.
The fact that so little lithium is available on the planet is one of the reasons why vehicles produced at very large scales will never be electric vehicles or hybrids. I remember reading somewhere that if you had every ounce of lithium on the planet right now that is reasonably expected to exist(regardless of the cost) available you couldn't make enough batteries for 1/5 of the vehicles in the USA that are currently on the road. Nevermind the rest of the world.