The Trump administration released its far-reaching rollback of Obama-era tailpipe pollution standards Tuesday, describing the new looser rules as reflecting its “largest deregulatory initiative” yet.

Instead of improving fuel ­efficiency by about 5 percent a year, the new standards require a 1.5 percent annual improvement through model year 2026, which will result in sharp increases in greenhouse gas emissions.

An earlier draft of the rollback envisioned freezing the standards, requiring no improvement in fuel efficiency in those years. But following broad pushback, including from environmental experts as well as some carmakers, administration officials said they opted to require modest gains in efficiency.

James C. Owens, acting administrator of the National Highway Traffic Safety Administration, which spearheaded the rulemaking effort, said the final proposal was changed to incorporate more than 750,000 public comments.

Academic experts and advisers to the federal government had called the administration’s analysis into question, pointing to errors and faulty assumptions.

Owens said “significant changes were made to the analysis” after considering “hundreds of highly technical comments.”

Administration officials asserted that the rule would lead to 3,300 fewer traffic fatalities over the lives of the cars built with the new standards, arguing that more people would get into newer, safer cars because they would be more affordable. An earlier draft had projected the weaker rules could save 12,700 lives over the coming decades, but the assumptions in those calculations were widely assailed.

The claimed potential for lower traffic deaths under the new rules also does not account for increases in deaths due to illnesses from greater pollution. The rule projects between 440 and 990 premature deaths would occur due to air pollution during that same period, though Environmental Protection Agency officials said the number may be slightly lower.

“Today, President Trump is keeping his promise to autoworkers made three years ago that he would reinvigorate American auto manufacturing by updating costly, increasingly unachievable fuel economy and vehicle CO2 emissions standards,” Transportation Secretary Elaine Chao said in a statement.

But Rep. Debbie Dingell (D-Mich.), who represents a district with a heavy auto industry presence, said the rules will cause “serious and detrimental harm to an industry that needs certainty.”

“The Administration’s inability to work with all stakeholders to develop a consensus proposal will cause more uncertainty and chaos for an industry recently turned on its head by the COVID-19 epidemic,” Dingell said in a statement, adding that more litigation is sure to follow.

Officials in California, which sets higher fuel-efficiency standards shared by many other states, said the new rules would not accomplish what the administration claims they will.

In a statement from the office of Attorney General Xavier ­Becerra (D), who has helped lead legal challenges to the administration rollback, California officials said the rule will “fail to increase fuel economy.” That’s because the ­industry is already making ­improvements “on their own at 2 percent without the rule,” the statement said.

They also wrote that the rule “will not save lives” and “is a wash at best. Increased air pollution will likely take more lives than the plan purports to save.”

Becerra said the rules violate federal law and the state is prepared to take legal action.

In the 1,975-page rule itself, the agencies billed the changes as “gradual, tough, but feasible,” saying they “take into account real world performance, shifts in fuel prices, and changes in consumer behavior toward crossovers and SUVs and away from more efficient sedans.”

The rule contains a kind of environmental paradox: Because consumers are not flocking to fuel-efficient vehicles, the EPA concluded it would be unfair to hold automakers to higher fuel-efficiency standards.

The result, by the agency’s own analysis, is that the new standards would lead to an additional 2 billion barrels of fuel being burned in coming years. That amounts to as much as 923 million more metric tons of carbon dioxide being emitted, and is equivalent to the emissions from running 237 coal power plants for a year, according to the EPA’s online calculator.

Nonetheless, the agencies concluded that the changes were justified.

The EPA said it considered low fuel prices and consumers’ interest in less fuel-efficient SUVs as reasons for lowering the ­fuel-efficiency targets, questioning whether automakers would have struggled to meet the existing standards in time based on what their customers want.

“Consumer demand, and willingness to pay for technology that reduces CO2 emissions and improves fuel economy, has not matched required standards — which is one of the reasons that EPA is revising the standards today,” the agency wrote.

State officials in Colorado criticized the final rule, echoing concerns that the 1.5 percent annual increase in standards does too little to nudge the industry toward progress. That figure “is lower than the average actual increases in efficiency achieved per year since the Bush Administration,” Colorado officials said in a statement.

While Ford and a group of other automakers reached a compromise with California last year to follow higher standards than required by Washington, some other carmakers, including General Motors, sided with the Trump administration in its fight over the state’s approach.

A GM spokesman did not answer questions on whether the rules would prompt more sales and safer roads, as administration officials argue. The maker of the Chevrolet Bolt EV instead reiterated its call to buttress spending on a national incentives program to promote sales of millions more electric vehicles and to support U.S. battery makers.

“The best way to remove automobile emissions from the environmental equation is an all-electric, zero emissions future,” according to the statement.

In a tweet Tuesday, Trump knocked “foolish executives” from “politically correct Automobile Companies.” He asserted the changes would lower car prices “by more than $3500” and have a “positive impact” on the environment, while “making the cars substantially safer.” Those claims are inaccurate or contradicted by information released by his agencies. The Transportation Department says Trump’s rule would cut car prices by “about $1,000.” Lowering the standards will add pollution, not make it better. And the administration rule does not govern the safety of automobiles.

Owens said the new rules, as mandated by Congress, reflected a careful weighing of economic, technological, conservation and safety considerations, not “the very narrow case of just fuel economy.”

“This is not politics, this is policy,” Owens said, adding that officials are “prepared to defend the rule” in court.

Former vice president Joe Biden and Sen. Bernie Sanders (I-Vt.) would both jettison the Trump rollbacks if elected president, as part of what they said would be more ambitious environmental measures.

Juliet Eilperin contributed to this report.