WASHINGTON — The United States government on Thursday announced the repeal of a scientific finding that greenhouse gas emissions endanger human health, and eliminated federal tailpipe emissions standards for cars and trucks.

The endangerment finding was first adopted by the US in 2009, and led the EPA to take action under the Clean Air Act of 1963 to curb emissions of carbon dioxide, methane, and four other heat-trapping air pollutants from vehicles, power plants and other sources.

It is the most sweeping climate change policy rollback by the administration of President Donald Trump to date, after a string of regulatory cuts and other moves intended to unfetter fossil fuel development and stymie the rollout of clean energy.

"Under the process just completed by the EPA (Environmental Protection Agency), we are officially terminating the so-called endangerment finding, a disastrous Obama-era policy that severely damaged the American auto industry and drove up prices for American consumers," Trump said, saying it was the biggest deregulatory action in US history.

Trump has previously said he believes climate change is a "con job" and withdrawn the US from the Paris Agreement, leaving the world's largest historic contributor to global warming out of international efforts to combat it. He has also signed legislation killing tax credits aimed at accelerating deployment of electric cars and renewable energy.

The Alliance for Automotive Innovation, representing major automakers, did not endorse the action but said "automotive emissions regulations finalized in the previous administration are extremely challenging for automakers to achieve given the current marketplace demand for EVs".

The Environmental Defense Fund, a New York-based advocacy group, said the repeal will end up costing US people more, despite the claim that climate regulations have driven up prices for consumers.

Several environmental groups, including the Natural Resources Defense Council, announced they will challenge the reversal in court, setting off what could be a yearslong legal battle up to the Supreme Court.

Former US president Barack Obama blasted the move on X, saying without the endangerment finding, "we'll be less safe, less healthy and less able to fight climate change — all so the fossil fuel industry can make even more money".

Agencies Via Xinhua