President Donald Trump has signed an executive order rolling back Obama-era rules aimed at curbing climate change.
The Energy Independence Executive Order suspends more than half a dozen measures enacted by the president’s predecessor, and boosts fossil fuels.
Among the initiatives now rescinded is the Clean Power Plan, which required states to slash carbon emissions.
Business groups have praised the Trump administration’s move but environmental campaigners have condemned it.
Before he signed the order, the president said this would put an end to the “war on coal” and “job-killing regulations”.
During the campaign, he vowed to pull the US out of the Paris climate deal agreed in December 2015.
The White House said the new measures would “help keep energy and electricity affordable, reliable and clean in order to boost economic growth and job creation”.
But environmental groups warn that they will have serious consequences at home and abroad.
President Trump takes a very different approach to the environment from Obama. The former president argued that climate change was “real and cannot be ignored”.
The Clean Power Plan sought to limit greenhouse gas emissions at coal-fired power plants to meet US commitments under the Paris accord.
The regulation has been unpopular in Republican-run states, where it has been subject to legal challenges – especially from businesses that rely on burning oil, coal and gas.
Last year the Supreme Court temporarily halted the plan, while the challenges are heard.
The Trump administration says that scrapping the plan will put people to work and reduce America’s reliance on imported fuel.
It says the president will be “moving forward on energy production in the US”.
“The previous administration devalued workers with their policies. We can protect the environment while providing people with work.”
During the president’s maiden visit to the Environmental Protection Agency, he signed the Energy Independence Executive Order, which cuts EPA regulations in order to support Trump’s plan of cutting the agency’s budget by a third.
The President recently appointed climate change sceptic Scott Pruitt as the new head of EPA.
Billionaire environmental activist Tom Steyer was quoted by Reuters as saying: “These actions are an assault on American values and they endanger the health, safety and prosperity of every American.
Also, David Doniger of the Natural Resources Defense Council said: “I think it is a climate destruction plan in place of a climate action plan,” adding that they will fight the president in court.
Another green group, Earthjustice, also said it would challenge the measure in and out of court.