Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

OHIO ET AL v. ENVIRONMENTAL PROTECTION AGENCY ET AL

ON APPLICATIONS FOR STAY

No. 23A349. Argued February 21, 2024—Decided June 27, 2024* The Clean Air Act envisions a collaborative effort between States and the federal government to regulate air quality. When the Environmental Protection Agency sets standards for common air pollutants, States must submit a State Implementation Plan, or SIP, providing for the “implementation, maintenance, and enforcement” of those standards in their jurisdictions. See 42 U. S. C. §7410(a)(1). Because air currents can carry pollution across state borders,