The Natural Resources Defense Council challenged an Environmental Protection Agency revision to the Clean Air Act that redefined ‘new or modified major stationary sources’ of air pollution to allow plants to get permits for any equipment that did not meet standards on the condition that total emissions from the plant did not increase. Chevron appealed a federal court’s decision in favor of the NDRC as an affected party. The ruling gave federal agencies more independence in interpreting their roles. “Gave breathing room for agencies to grow into the fourth estate.” (Joseph Thai, clerk, 2000-2001.)

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