The U.S. Supreme Court has declined to review the environmental case of Ohio vs. EPA, allowing a lower court's decision to stand that supports California's authority to set its own vehicle emissions standards. This decision is viewed as a victory for California, particularly concerning its Advanced Clean Trucks rule. The ruling came after an appeal from 17 conservative states challenging the EPA's 2022 waiver that permits California to implement stricter air pollution controls. The Supreme Court's ruling was 8-1, with Justice Clarence Thomas dissenting. Additionally, the Court has indicated it will review another case related to the automotive industry's ability to challenge California's emissions regulations, which could further impact state-level environmental policies.