The Environmental Protection Agency (EPA) is taking final action to approve a State Implementation Plan (SIP) submission, submitted by the State of Mississippi, through the Mississippi Department of Environmental Quality (MDEQ), on June 26, 2018. This SIP submission addresses specific Clean Air Act (CAA or Act) requirements applicable to Mississippi state boards or bodies that approve CAA permits or enforcement orders. This submission also specifically addresses related requirements for implementation of the following national ambient air quality standards (NAAQS): 2008 8-hour Ozone, 2008 Lead, 2010 Nitrogen Dioxide (NO<INF>2</INF>), 2010 Sulfur Dioxide (SO<INF>2</INF>), and 1997, 2006 and 2012 fine particulate matter (PM<INF>2.5</INF>). Whenever EPA promulgates a new or revised NAAQS, the CAA requires the state to make a new SIP submission establishing that the existing SIP meets the various applicable requirements, or revising the SIP to meet those requirements. This type of SIP submission is commonly referred to as an "infrastructure" SIP. In this final action, EPA is approving the June 26, 2018, submission with respect to the CAA requirements applicable to state boards; and the related state board infrastructure SIP requirements for the 2008 8-hour Ozone, 2008 Lead, 2010 NO<INF>2</INF>, 2010 SO<INF>2</INF> and 1997, 2006 and 2012 PM<INF>2.5</INF>, NAAQS. This action removes EPA's obligation to promulgate a Federal Implementation Plan (FIP) to address these CAA state board requirements for Mississippi.