The Environmental Protection Agency (EPA) is finalizing approval on a revision to the North Dakota State Implementation Plan (SIP) submitted by the State of North Dakota on November 11, 2016 and supplemented on March 15, 2021, that addresses amendments to the regional haze provisions of the North Dakota Administrative Code (NDAC). These revisions were submitted to remove certain regional haze requirements related to Best Available Retrofit Technology (BART) in the first planning period. EPA is also finalizing approval on a revision to the North Dakota SIP submitted on August 3, 2020, that addresses additional amendments to the regional haze provisions of the NDAC. The 2020 SIP revision was submitted to update the incorporation by reference date for regional haze definitions, add emission reduction requirements to make reasonable progress during the second and subsequent regional haze planning periods, and revise the regional haze monitoring, recordkeeping, and reporting requirements to be applicable under the second and subsequent planning period. EPA is taking this action pursuant to section 110 and Part C of the Clean Air Act (CAA).