(a) [Reserved]

(b) Tennessee submitted a letter to EPA on November 15, 2019, with a commitment to address the State Implementation Plan deficiencies regarding the PSD-related requirements of CAA sections 110(a)(2)(C), 110(a)(2)(D)(i)(II) (Prong 3), and 110(a)(2)(J) for the 2015 8-hour ozone NAAQS. EPA conditionally approved these portions of Tennessee's September 13, 2018, infrastructure SIP submission in an action published in the Federal Register on April 9, 2020. If Tennessee fails to meet its commitment by April 9, 2021, the conditional approval will become a disapproval on that date and EPA will issue a notification to that effect.