Clean Air – Environmental and Energy Law Program

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.

July 22, 2026

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.

July 17, 2026

Regulatory Tracker

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

The EPA rescinded the Endangerment Finding and all GHG vehicle standards.

July 9, 2026

Quick Takes

D.C. Circuit Upholds EPA’s 2024 Fine Particulate Matter Standard

Analyzis of the legal challenges to the standard and how the D.C. Circuit’s rejection of those challenges may affect future air quality rulemakings.

July 8, 2026

Regulatory Tracker

New Source Review

EPA establishes the baseline requirements for new source review (NSR) permits, which are then issued by state and local air pollution agencies. In 2025 and 2026, EPA made changes to the NSR program easing permitting requirements.

July 7, 2026

Quick Takes

A Legal Challenge with Major Implications for Citizen Suits

DOJ intervenes in and moves for dismissal of citizen suit, citing primacy of its own enforcement discretion

June 16, 2026

Regulatory Tracker

Power Plant Startup, Shutdown, and Malfunction Rule

In June 2026, EPA partially withdrew SSM SIP Call findings of failure to submit, leaving four state agencies with outstanding SSM revision obligations.

June 12, 2026

Legal Analysis

EPA Proposes to Limit Its Responsibility to Revise Hazardous Air Pollution Standards

Analysis of the proposal regarding previously unregulated hazardous air pollutant emission points, the agency’s legal rationale, and the implications for EPA’s broader obligations under the Clean Air Act.

June 9, 2026

Regulatory Tracker

Implementation of 2015 Ozone National Ambient Air Quality Standards (NAAQS)

Under the Trump executive order Regulatory Freeze Pending Review, the Biden administration’s final rule setting deadlines for states to submit SIPs for nonattainment areas did not go into effect. On June 3, 2025, EPA announced its plans to reconsider the rule.

June 9, 2026