President Donald Trump pardoned nine individuals convicted of Clean Air Act violations related to vehicle modifications.

The Clean Air Act regulates emissions from motor vehicles and industrial sources.

The individuals were found guilty in federal court for altering emissions control systems in diesel trucks.

Prosecutors said the modifications increased nitrogen oxide and particulate matter output.

The Department of Justice announced the convictions in 2023 after a multi‑state investigation.

The White House said the pardons were part of a broader review of sentencing disparities.

Environmental advocacy groups criticized the decision, saying it undermines enforcement of environmental laws.

The Environmental Protection Agency has not issued a public statement on the matter.

The nine individuals will have their convictions erased, but the underlying violations remain subject to future regulatory action.

Legal experts note that the pardon does not affect ongoing civil penalties imposed by the EPA.