Four Republican U.S. senators on Thursday proposed repealing landmark California vehicle emissions rules in a bid to prevent the state from imposing stricter tailpipe requirements than the federal government.

The U.S. Environmental Protection Agency in June sent the Republican-controlled Congress landmark state vehicle emissions rules for potential repeal, saying the waivers granted under the Clean Air Act for California environmental regulations approved under prior Democratic administrations should have been sent to lawmakers under the ​Congressional Review Act. California sued to block the action in federal court.

(Reporting by David ShepardsonEditing by Nick Zieminski)