Fuel Cell vehicles are available in limited quantities, e.g. http://world.honda.com/FuelCell/ , but the major challenges are that the cells themselves aren't really competitive with other fuel sources yet, and places to refuel the vehicles are scarce.
These days we r facing the problem or can say major problem of pollution. To keeping control on pollution is basicaly called "POLUTION UNDER CONTROL" there is many sources of pollution one of them is gases emmerging from cars. to control the pollution by cars the test of PUC has to b done on car.