The Environmental Protection Agency (EPA) is approving, under the Clean Air Act (CAA), a request submitted by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) on December 18, 2020, to revise the Michigan State Implementation Plan (SIP). EGLE's submittal addresses the emissions inventory and statement requirements for the Allegan County, Berrien County, Detroit (Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne Counties) and Muskegon County nonattainment areas under the 2015 ozone National Ambient Air Quality Standard (NAAQS or standard).