On Monday, the Environmental Protection Agency announced the finalization of regulations that would boost the current fleet of environmentally friendlier vehicles, resulting in 17% of cars on the road in the country either being an EV or plug-in hybrid. The vehicles impacted by the new standard are light-duty vehicles like passenger cars or trucks that weigh no more than 8,500 pounds manufactured in 2023 and beyond. There will likely be tighter restrictions implemented along the way, as the Biden administration set a goal for 50% of U.S. vehicles to be either EVs or hybrids.

EPA Administrator Michael Regan praised his agency’s efforts, which he said resulted from taking science and stakeholders into consideration. “At EPA, our priority is to protect public health, especially in overburdened communities, while responding to the president’s ambitious climate agenda,” Regan said in a press release. “We take a giant step forward in delivering on those goals while paving the way toward an all-electric, zero-emissions transportation future.” According to the Department of Energy, more hybrids certainly make for fewer emissions but still emit significantly more greenhouse gases than EVs. Whereas one EV emits about 3,783 pounds of greenhouse gases annually, a plug-in hybrid releases 5,685 pounds annually, while a standard hybrid releases 6,258 pounds per year.

As renewable technology continues to advance, automakers and consumers will be able to make the most out of low-emissions vehicles, which likely lead to a further drop in emissions. Experts believe much of this comes down to the way countries are powered, specifically how quickly major polluters like the U.S. transition away from non-renewable resources to more eco-friendly options. “We are projecting that with cleaning up the grid, we can reduce emissions from electric vehicles by 75%, from about 200 (grams) [7 ounces] today to about 50 grams [1.8 ounces] of CO2 per mile in 2050,” MIT Energy Initiative Senior Research Scientist Sergey Paltsev told CNBC.

Another matter to consider is the upfront environmental cost of producing EVs and hybrids, which pale in comparison to long-term light vehicle use, but are nonetheless substantial. As Politico notes, the supply chain itself would have to undergo a major shift and require the cooperation of other countries like China, which controls 80% of the world’s lithium battery supply chain. Lithium-ion battery production does indeed carry with it a cost: For example, producing a Tesla Model 3’s 75-kilowatt-hour battery at the company’s Nevada factory would result in the emission of more than 9,900 pounds. Mining raw materials also plays a role in emissions, accounting for more than 33,000 pounds of CO2 per every tonne of lithium mined using traditional methods.

Alternatives do exist and could substantially lower emissions in the mining sector. Though the EPA’s latest regulations are an encouraging sign, they also point to just how multifaceted of an issue it is to reduce emissions. The rules have the backing of prominent players like the United Auto Workers, Ford, and lawmakers like California Gov. Gavin Newsom. It’s a great start that the U.S.—and the world—can and must build upon, especially if the U.S. were to reach its EVs and hybrids goal by 2030.