Clean Air – Environmental and Energy Law Program

Regulatory Tracker

Regulating Greenhouse Gases for New and Existing Fossil Fuel-Fired Power Plants

In June 2025 EPA proposed a rule rolling back the 2024 EPA standards for GHG emissions from existing coal-fired power plants and new gas-fired power plants.

February 12, 2026

Legal Analysis

The Congressional Review Act in 2025: Expanding Use and Emerging Questions

After decades of limited use, Congress used the Congressional Review Act 22 times in 2025, testing the boundaries of congressional power, agency rulemaking, and the courts’ role in reviewing CRA actions.

February 5, 2026

Regulatory Tracker

Air Transport Rules: Cross-State Air Pollution Rule/Good Neighbor Plan Rule

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.

January 30, 2026

Regulatory Tracker

Clean Car Rules — Corporate Average Fuel Economy Standards/Greenhouse Gas Standards

The Trump EPA issued a proposal to rescind the Endangerment Finding and the GHG standards for light, medium, and heavy-duty vehicles.

January 27, 2026

Regulatory Tracker

Regional Haze Rule

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

January 26, 2026

Regulatory Tracker

Once In Always In Guidance for Major Sources under the Clean Air Act

Congress repealed the 2024 rule using the Congressional Review Act and EPA reinstated the 2020 rule, which allows a major source to reclassify as an area source if the source reduces HAP emissions.

January 2, 2026

Regulatory Tracker

Power Plant Startup, Shutdown, and Malfunction Rule

In early January 2025, the Biden EPA withdrew its direct final rule and indicated it would release a subsequent rule addressing the 13 states that failed to submit state implementation plan revisions.

January 2, 2026

Regulatory Tracker

EPA VOC and Methane Standards for Oil and Gas Facilities

The Biden EPA finalized three rules regulating methane emissions from the oil and gas sector. One of the rules, the Waste Emission Charge, was repealed using the Congressional Review Act. In Sept. 2025, EPA proposed to delay the GHG reporting rules until 2034. In Nov. 2025, EPA finalized the deadline exemptions for certain provisions regulating methane emissions from new and existing oil and gas sources.

December 4, 2025

Regulatory Tracker

National Ambient Air Quality Standards (NAAQS) for Particulate Matter (PM)

The CAA requires EPA to review and set primary and secondary standards for PM NAAQS every 5 years. The Biden EPA strengthened the standard in March 2024. On November 25, 2025, EPA requested the D.C. Circuit vacate the 2024 rule.

November 24, 2025