The EPA is finalizing a Federal Implementation Plan (FIP) under the Clean Air Act (CAA or Act) for Indian country. The FIP includes two New Source Review (NSR) regulations for the protection of air resources in Indian country. The first rule applies to new and modified minor stationary sources (minor sources) and to minor modifications at existing major stationary sources (major sources) throughout Indian country. The second rule (nonattainment major NSR rule) applies to new and modified major sources in areas of Indian country that are designated as not attaining the National Ambient Air Quality Standards (NAAQS). These rules will be implemented by EPA or a delegate Tribal agency assisting EPA with administration of the rules, until replaced by an EPA-approved implementation plan.