The Environmental Protection Agency (EPA) is approving a regional haze progress report State Implementation Plan (SIP) revision submitted by the State of Wyoming on November 28, 2017. The revision addresses the requirements for states to submit periodic reports describing progress toward reasonable progress goals established for regional haze and a determination of adequacy of the State's existing regional haze SIP and federal implementation plan (FIP). The EPA is taking this action pursuant to section 110 of the Clean Air Act (CAA).