The Environmental Protection Agency has outlined plans to undo a landmark Obama-era rule tightening fuel standards for vehicles, weakening the only major federal policy to reduce planet-warming emissions from the nations top source of greenhouse gas pollution.

The decision, announced Monday in a press release, hands a victory to automakers who lobbied the Trump administration to declare the previous standard too strict.

The Obama administrations determination was wrong, EPA Administrator Scott Pruitt said in a statement, adding that the standards were too high.

At a press conference Tuesday morning, Pruitt, flanked by signs that read CERTAINTY, JOBS and EFFICIENCY, compared the nations economic optimism over his deregulatory efforts to the excitement over a new baseball season. Three executives from auto industry trade associations joined Pruitt at the event.

Pruitt, who is facing mounting calls to resign, heaped praise on President Donald Trump , who reportedly called the embattled administrator Tuesday morning to offer his support.

The press conference was originally scheduled to be held at a Chevrolet dealership in Chantilly, Virginia, that is owned by Geoffrey Pohanka, an outspoken climate change denier and National Automobile Dealers Association board member. But other Chevy dealers, wary of associating the General Motors brand with the Trump administrations actions, convinced Pohanka to cancel the event, according to The New York Times . Instead, Pruitt hosted the conference in the EPAs historic Rachel Carson Green Room.

Pruitt did not take any questions.

The federal rule required vehicles to average 54.5 miles per gallon by 2025, nearly double todays standard. The new standard provided significant environmental and financial benefits if fully implemented. Under those rules, oil consumption would fall by 12 billion barrels , tailpipe emissions would halve and fuel efficiency would nearly double, saving consumers $3,200 to $5,700 in gasoline costs over a vehicles lifetime. The regulation would have prevented 6 billion metric tons of planet-warming gases equivalent to a years worth of pollution from 150 power plants from ever entering the atmosphere.

In its 38-page finding , the EPA cited lower gas prices and changes to consumer acceptance of advanced technology vehicles as reasons the original determinations no longer represent realistic assumptions. The agency also said it planned to reconsider how climate change factored in to regulation, noting that the social cost of carbon and energy security valuation ... should also be updated to be consistent with the literature and empirical evidence. The memo made no explicit mention of climate change.

Automakers agreed to the rule in 2012 as part of the first major overhaul of fuel efficiency standards since the 1970s. But the policy set an April 2018 deadline to review the standards and tweak them if they proved too expensive or impossible to meet. In January 2017, the Obama administration attempted to lock the regulation in place by issuing a positive assessment of the costs and feasibility of the regulations.

Despite overwhelmingly supporting the agreement seven years ago, carmakers began lobbying Trump to reverse the Obama ruling almost immediately after the 2016 election. Automakers missed their emissions target for the first time last year, even though they achieved record fuel economy, in part because the companies boosted production of gas-guzzling SUVs .

Last March, the White House tossed the assessment out at an event in Detroit, insisting the analysis was rushed. Trump vowed to restore the originally scheduled midterm review. The EPAs latest announcement is the result of that review.

The decision to rewrite the rule puts the EPA at loggerheads with California regulators, who agreed in 2011 as part of the rule to align their tailpipe emissions standards with the national levels. The deal guaranteed consistent mileage and emissions rules nationwide, allowing automakers to save money by manufacturing vehicles to one standard.

Undoing the rule threatens to upend that uniformity. Under the Clean Air Act, California is allowed to set vehicle emissions standards higher than the rest of the country, and with nearly 35.4 million registered vehicles, the state commands powerful influence over the American auto market. A dozen other states, including New York, Massachusetts and Pennsylvania, have historically followed Californias lead.

The EPA said the California waiver was still being reexamined by Pruitts team.