Mississippi submitted a SIP revision to EPA on January 25, 2021, as supplemented on November 18, 2022, regarding Mississippi's 2015 8-hour Ozone NAAQS infrastructure SIP that addresses the prevention of significant deterioration related requirements of CAA sections 110(a)(2)(C), 110(a)(2)(D)(i)(II) (Prong 3), and 110(a)(2)(J), and the modeling requirements of 110(a)(2)(K). The SIP revision included a commitment to adopt a rule revision to meet requirements of these sections and submit a SIP revision containing the revised rules. EPA conditionally approved these portions of the January 25, 2021, SIP revision, as supplemented November 18, 2022, in an action published in the Federal Register on March 1, 2023. If Mississippi fails to meet its commitment by March 1, 2024, the conditional approval will become a disapproval on March 1, 2024.