On March 3, 2023, the D.C. Circuit Court of Appeals rejected an industry challenge to the April 2021 Revised Cross-State Air Pollution Rule (CSAPR) Update Rule from the Environmental Protection Agency (EPA or Agency), which required power plants in 12 “upwind” states to reduce nitrogen oxide (NOx), an ozone precursor, emissions such that those states did not inhibit downwind states’ ability to comply with the 2008 Ozone National Ambient Air Quality Standard (NAAQS).

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