In accordance with the Clean Air Act (CAA), the Environmental Protection Agency (EPA) is redesignating the Southwest Indiana nonattainment area, which consists of a portion of Daviess County and a portion of Pike County (Veale Township in Daviess County and Washington Township in Pike County), to attainment for the 2010 primary, health- based 1-hour sulfur dioxide (SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS). EPA is also approving Indiana's maintenance plan for the Southwest Indiana SO<INF>2</INF> nonattainment area. Indiana submitted the request for approval of the Southwest Indiana nonattainment area's redesignation and maintenance plan on October 24, 2018, and supplemental information on August 25, 2020. EPA has previously approved Indiana's attainment plan for the Southwest Indiana area.