Under the Clean Air Act, California has the ability to enact its own air pollution laws due to unique and extreme impacts of pollution in the state. In order to implement stricter regulations, California must acquire a waiver from EPA and the state has done this nearly fifty times over the last three decades. Previous waivers allowed California to create laws requiring catalytic converters, unleaded gasoline, and other major advancements in air pollution reduction, which are often implemented on the national level.
Haughey, Addie. “California Sues EPA After ‘Unconscionable’ Waiver Denial.” Sustainable Development Law & Policy, Winter 2008, 14, 82.