California Governor Gavin Newsom announced an executive order Wednesday requiring that all new passenger cars and trucks sold in the state be zero-emission vehicles by 2035. The effort is aimed at curbing carbon emissions in the country’s most populous state and addressing the climate change crisis. The transportation sector is responsible for more than half of the state’s carbon pollution, according to Newsom’s office. The announcement comes after Californians have for weeks been battered by an unprecedented wildfire season. The vast majority of scientists agree that climate change-driven disasters will inevitably increase. “This is the most impactful step our state can take to fight climate change,” Newsom said in a release. “Californians shouldn’t have to worry if our cars are giving our kids asthma. Our cars shouldn’t make wildfires worse — and create more days filled with smoky air. Cars shouldn’t melt glaciers or raise sea levels threatening our cherished beaches and coastlines.” The order relates only to new car sales. It would not prevent Californians from owning or driving gasoline-powered cars, or buying or selling them on the used car market, according to the release. It’s unclear exactly how the order will be implemented. Following the order, the California Air Resources Board has been charged with developing new regulations mandating that all in-state sales of passenger cars and trucks be zero-emission by 2035. The board is also developing regulations that would require all medium- and heavy-duty vehicles to go emissions-free by 2045 “where feasible,” though the mandate stays at 2035 for harbor shipping operations vehicles. In order for the mandate to be carried out, the release said California state agencies will partner with the private sector to develop the infrastructure to support what would likely amount to more widespread usage of electric vehicles, such as more charging stations throughout the state. The order is a bold move that would follow the lead of several cities and countries around the world. California would be the US state to implement such a policy. But it’s likely to be unpopular with at least some auto manufacturers — the switch to widespread production of all-electric vehicles, while already underway for most major manufacturers, is costly — and they could could challenge the order in court. Then again, the order could be just the kind of push needed to get the auto industry moving more aggressively toward a strategy centered on electric vehicles, according to Jessica Caldwell, director of insights at Edmunds, an online resource for car data. “The automotive industry was already on the road toward electrification as a long term goal, but many automakers have been guilty of setting short term targets for their electrification strategy that never came to fruition,” Caldwell said in an emailed comment. “This rule, if implemented, establishes a specific timeline that they’ll collectively need to adhere to. California is a major market that automakers desperately need to maintain sales within to ensure their own viability.” Newsom’s order also comes in the midst of California’s court battle with the Trump administration over the state’s ability to set its own emissions standards, which could be another hurdle for the order’s implementation. There is also a question of affordability and equity for low-income communities, as electric cars tend to be more expensive than their gas-powered counterparts, at least for now. The governor’s press release announcing the order noted that, “zero-emission vehicles will almost certainly be cheaper and better than the traditional fossil fuel powered cars” by the time the rule goes into effect. In a press conference about the order Wednesday, Newsom’s staff also pointed to private sector developments, such as a prediction by Tesla CEO Elon Musk Tuesday that more efficient batteries will be mainstream in the next three to four years, which would significantly reduce the costs of electric vehicles.