The Environmental Protection Agency (EPA) is approving the Regional Haze State Implementation Plan (SIP) revision submitted by the Ohio Environmental Protection Agency (Ohio or Ohio EPA) on July 30, 2021, as supplemented on August 6, 2024, and clarified by Ohio on June 16, 2025, as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule for the program's second implementation period. Together, Ohio's 2021 SIP submission, 2024 SIP supplement, and 2025 clarification address the requirement that States must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. Ohio's complete SIP submission also addresses other applicable requirements for the second implementation period of the Regional Haze Program. EPA is taking this action pursuant to sections 110 and 169A of the CAA.