Washington (CNN) President Donald Trump has repeatedly vowed to "ensure" that the United States has the "cleanest air" and the "cleanest water," but his administration's efforts to slash environmental regulations have been extensive.

In Trump's first two years in office, the Environmental Protection Agency's rate of deregulation was so high that an internal watchdog has said the agency " exceeded " its self-established goals. And in the third year of his presidency, agencies, not just the EPA, have continued the environmental regulation rollbacks. His administration has even moved to rollback some protections established under the 50-year-old Clean Air Act

Breaking away from environmental restrictions deemed cumbersome or unfair also became a global issue early in Trump's presidency, with his decision to pull out of the Paris climate accords -- an agreement among several countries to combat climate change.

Scientific experts, including members of the EPA's own scientific advisory board, have asserted that axing and altering these rules and regulations will be detrimental toward the environment. But the administration has asserted that they've removed cumbersome restrictions while continuing to protect the environment and expanding economic opportunity for energy companies, farmers and other commercial industries.

Here's a list of many of the major environmental rollbacks the Trump administration has attempted to undertake.

Oil, natural gas, methane and power

Last year, the EPA finalized a rule replacement for the Clean Power Plan, an Obama-era proposal which would have required states to meet targets to reduce greenhouse gas emissions. The Trump administration's replacement states can set their own carbon emissions standards for coal-fired power plants -- a rule that the agency itself says could result in 1,400 more premature deaths by 2030 than the Obama-era plan it will replace.

Additionally, the EPA proposed last year to ease regulation of methane emissions, a particularly potent greenhouse gas believed to contribute significantly to climate change. The Trump administration has asserted that the Obama administration improperly regulated the emissions.

The EPA recently proposed scaling back the requirements for storing and releasing waste from coal-fired power plants, despite also finding an increase in toxic leaks from waste pits. The agency has also recently proposed granting Georgia authority to regulate in its state the handling of coal ash, despite calls for increased regulation in the state over their compromised handling of the byproduct. Around the same time as the proposed change in Georgia, the EPA also announced it would expand a temporary and voluntary "self-audit" program for oil and natural gas explorers and producers that would cut penalties for polluters that discover, self-report and fix problems.

Trump has frequently complained about the orange hue that results from energy efficient lightbulbs. In 2019, the Energy Department blocked stricter efficiency requirements for many common types of lightbulbs that would have taken effect in 2020. The government, consumer groups and environmentalists have disputed how much the standards, developed under the Obama administration and based on a Bush-era law, would cost or save.

And earlier this month, the Trump administration announced planned changes to National Environmental Policy Act rules, which require federal agencies to assess the environmental impact of projects such as the construction of mines, highways, water infrastructure and gas pipelines. The proposal would set limits on environmental assessments and changes what impacts must be considered, two significant moves that could make it easier to approve projects.

Automobiles

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In 2018, the Trump administration sought to freeze fuel economy standards at static levels beginning in 2020. But this week, in a concession, the administration proposed an increase of 1.5% per year from 2021 through 2026, according to Democratic Sen. Tom Carper's office , which sent a letter to the administration about it.

The Trump administration is also ensnared in a lawsuit with the states of California and New York, which want to set their own auto emissions standards, which would be higher than those set by the federal government. Trump has personally argued that federal standards will "produce far less expensive cars for the consumer, while at the same time making the cars substantially SAFER."

But The Washington Post reported earlier this month that the administration's own analysis of Trump's plan concluded that it would cost consumers more than it would save them and would not make a large impact on car safety.

But despite earlier efforts to ease up on fuel efficiency regulations, this month the EPA also announced it would be pursuing a new rule aimed at cutting emissions from heavy duty trucks in order to reduce nitrogen oxides, which is linked to respiratory issues and creating smog.

Public lands

The Trump administration is responsible for the largest reduction in the boundaries of protected land in US history, according to a study in the journal Science. Under Trump, two major downsizes of protected lands have occurred -- the shrinking of protected land at the Grand-Staircase Escalante National Monument and Bears Ears, both in Utah. The changes enabled mining and oil and gas development, the study said.

Water

This week the EPA announced it will rescind Clean Water Act protections from many streams and wetlands, a rollback of what the agency says is unnecessary regulations, siding with requests from industry and farm groups over the advice of environmental experts and its own scientific advisers.

Wildlife

The administration has also finalized changes to Obama-era protections for the sage grouse bird, in a move which could open up areas meant to protect the species for oil and gas extraction.

The administration has also made changes to the Migratory Bird Treaty Act, which has severely limited any penalties for bird deaths across the United States.

Agriculture

Late last year, the EPA proposed increasing the allowable levels of the herbicide Atrazine, which is used commercially to kill weeds on crops and lawns. It said the proposal is one of several that would "ensure a strong and vibrant agricultural market."

The Centers for Disease Control and Prevention says the chemical does not break down if it is washed into groundwater or nearby streams, and that it has been linked to reproductive abnormalities including premature birth.