Clean Air

EPA rescinded the 2024 mercury and air toxics standards (MATS) for power plants and reinstated the 2012 MATS.

Through two state plan approvals, EPA finalized a new policy that eases all states’ Regional Haze planning obligations. Environmental groups are challenging the approvals.

EPA establishes the baseline requirements for new source review (NSR) permits, which are then issued by state and local air pollution agencies. In 2025, EPA made multiple changes to the NSR program easing permitting requirements for new and existing sources.

The Clean Air Act’s Good Neighbor provision requires upwind states to ensure that their instate sources do not contribute to downwind states’ attainment of the NAAQS. On Mar. 12, 2025, EPA announced its plan to roll back the Biden administration’s Good Neighbor Plan, which the Supreme Court stayed in June 2024.