The famous "California law" in the U.S. sets increasingly strict emissions standards, to go into effect in stages beginning in 1994, until in the year 2003 10 % of all the new cars in the state must be completely pollution-free vehicles.
美國著名的「加州法案」，將從一九九四年起分階段限制未來車輛汙染的程度。到西元二○○三年全州新出廠車輛，必須有百分之十是完全無汙染的車子。