Stop CARB Act of 2025

This bill would end the Clean Air Act waiver that lets California set its own stricter rules for new car and truck emissions, and it would also end the option for other states to copy California’s standards . It would cancel past waivers and automatically deny any pending waiver requests on the day it becomes law. The bill also blocks states and local governments from setting their own emission rules for certain nonroad engines and vehicles, including new construction and farm equipment and new locomotives. It makes related changes in other parts of the Clean Air Act, including fuel rules, to match these repeals.

Key points

• Who is affected: States (including California) and states that follow California’s vehicle rules; makers of new cars, trucks, and engines; operators of construction and farm equipment and locomotives; state and local governments that set air rules .
• What changes: Ends the California waiver; stops other states from using California’s standards; voids past waivers and denies pending ones; bars state rules for certain nonroad engines; updates related Clean Air Act provisions, including fuel sections .
• When: These changes take effect on the date the bill becomes law.