This joint resolution seeks to overturn an Environmental Protection Agency decision from 2009 that allowed California to set its own greenhouse gas emission standards for new vehicles, separate from federal standards. Under the Clean Air Act, California has historically been granted waivers to establish stricter pollution controls than the rest of the nation, and this particular waiver applied to vehicles from 2009 onwards. The resolution would eliminate the EPA's approval of California's standards, preventing the state from enforcing its own tailored emissions requirements for new motor vehicles. The measure affects automakers and California, which would lose its authority to maintain its stricter vehicle emission rules. This is a congressional disapproval resolution, which uses a fast-track process to challenge federal agency regulations.