EPA is approving a Tribal Implementation Plan ("TIP") submitted by the Mohegan Tribe of Indians of Connecticut ("the Tribe"). This revision adds new emission units to the Tribe's TIP, while maintaining an enforceable cap on nitrogen oxide emissions from stationary sources owned by the Mohegan Tribal Gaming Authority and located within the external boundaries of the Mohegan Reservation. The revision also provides the Administrator of The Mohegan Environmental Protection Department with enforcement authority for violations of the Mohegan TIP and establishes a right of appeal to the Director of Regulation and Compliance and the Mohegan courts. This action is intended to help attain the National Ambient Air Quality Standards (NAAQS) for ground-level ozone. This action is being taken in accordance with the Clean Air Act.