FILE PHOTO: U.S. President Donald Trump (L) listens to EPA Administrator Scott Pruitt after announcing his decision that the United States will withdraw from the Paris Climate Agreement, in the Rose Garden of the White House in Washington, U.S., June 1, 2017. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) - U.S. President Donald Trump on Thursday ordered the Environmental Protection Agency to speed up its decision-making on air quality permitting to make it easier for manufacturers to expand and open new plants.

“These actions are intended to ensure that EPA carries out its core missions of protecting the environment and improving air quality in accord with statutory requirements, while reducing unnecessary impediments to new manufacturing and business expansion essential for a growing economy,” Trump said in a memorandum.

It orders the EPA to make changes to the National Ambient Air Quality Standards program (NAAQS) to reduce “unnecessary barriers that are holding back manufacturing and business growth,” according to a White House statement.

The Sierra Club, the leading U.S. environmental advocacy group, assailed the order, saying it sought to “recklessly cut short the review of clean air permits.”

“This policy haphazardly attempts to bypass important scientific work that keeps millions of communities’ air clean, and it sets in motion a clear ploy to weaken the latest science-based smog pollution standard,” Mary Anne Hitt, Senior Director of the group’s Beyond Coal campaign, said in a statement.

Trump’s order requires EPA Administrator Scott Pruitt to act within one year on preconstruction permit applications and to process state implementation plans on meeting air standards within 18 months.

“State requests for regulatory relief due to emissions beyond their control, including exceptional events and international emissions,” should also be processed quickly by the EPA, the order said.

Pruitt, who has loyally executed Trump’s deregulatory agenda with plans to roll back Obama-era programs cutting emissions from power plants and vehicles, is facing ethics allegations in the U.S. Congress.