NEW YORK (Reuters) - A coalition of U.S. states has mounted a broad legal challenge against what it called the Trump administration’s illegal suspension of rules to improve the energy efficiency of ceiling fans, portable air conditioners and other products. The challenge, also joined by environmental groups, came after the U.S. Department of Energy last month delayed standards proposed under the Obama administration to reduce air pollution and operating costs associated with the products. Ten Democratic attorneys general, plus New York City and a Pennsylvania regulator, on Monday notified Energy Secretary Rick Perry of their plan to sue in 60 days for stalling proposed standards for air compressors, commercial boilers, portable air conditioners, power supplies, and walk-in coolers and freezers. The same group, excluding Maryland, on Friday petitioned the federal appeals court in New York to force the administration to implement ceiling fan efficiency standards that were to have taken effect two weeks ago, but have been delayed to Sept. 30. Implementation was delayed after White House Chief of Staff Reince Priebus on Jan. 20 directed federal agencies to put new regulations on hold until their new leaders could review them. The Obama administration issued a similar directive in 2009. The Energy Department said it does not comment on pending litigation. New York Attorney General Eric Schneiderman said adopting the “common-sense” efficiency standards would dramatically reduce air pollution, including from carbon dioxide, mercury and methane. He said enough electricity would be saved to serve 36 million households annually, and save consumers and businesses close to $24 billion. “Leaving the final rules in regulatory ‘limbo’ has very real, negative economic and environmental consequences, essentially frustrating Congress’ energy conservation goals,” the states said in their letter to Perry. The letter was signed by officials of California, Connecticut, Illinois, Maine, Maryland, Massachusetts, New York, Oregon, Vermont, Washington, New York City and the Pennsylvania Department of Environmental Protection. The Consumer Federation of America, the Natural Resources Defense Council and the Sierra Club on Monday sent Perry a similar letter threatening litigation. Both letters accused the Energy Department of ignoring its obligation under federal law to publish final efficiency rules in the Federal Register. In notices published last month, the Energy Department said Perry had only begun his job on March 3 and needed more time to conduct “further review and consideration of new regulations.” The petition is New York et al v U.S. Department of Energy et al, 2nd U.S. Circuit Court of Appeals, No. 17-918. 