The Environmental Protection Agency (EPA) is approving portions of the State Implementation Plan (SIP) submission, submitted by the State of Mississippi, through the Mississippi Department of Environmental Quality (MDEQ), on December 11, 2015, to demonstrate that the State meets the infrastructure requirements of the Clean Air Act (CAA or Act) for the 2012 annual fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standard (NAAQS). The CAA requires that each state adopt and submit a SIP for the implementation, maintenance and enforcement of each NAAQS promulgated by EPA, which is commonly referred to as an "infrastructure" SIP. Specifically, EPA is approving the portions of the submission that relate to the prevention of significant deterioration (PSD) requirements. All other applicable infrastructure requirements for the 2012 Annual PM<INF>2.5</INF> NAAQS have been addressed in separate rulemakings.