In the middle of a legal fight with President Donald Trump, the state of California (which would rank as the fifth-largest economy on the planet) has decided that all state agencies won’t buy any more gas-powered sedans, and new cars will have to fit its emission standards.

The move will be followed in January by the decision not to buy any vehicles that don’t match the state’s clean car rules. Several carmakers would be directly affected such as General Motors, Toyota and Fiat Chrysler. Only in 2018, the state spent $27 million on passenger vehicles from Chevrolet.

“The state is finally making the smart move away from internal combustion engine sedans,” California Governor Gavin Newsom said in a statement. “Carmakers that have chosen to be on the wrong side of history will be on the losing end of California’s buying power.”

Newsom’s decision is the latest episode on a legal fight with Trump on how much cars should pollute. Trump seeks to roll back standards implemented by Obama to reduce emissions and increase fuel economy on passenger vehicles.

Although the new standards haven’t been finished yet, back in September the Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) removed California the authority of enacting its own rules on greenhouse gases. This led to a long court battle between a group of 23 states and the federal government, having already sued the EPA and the NHTSA. Meanwhile, California reached a deal with four carmakers, with the state relaxing Obama-era rules and the companies following California’s standards. It’s a delicate battle between states and the federal government — but it’s certainly ironic (and a touch sad) that the government is in the anti-environmental camp.

Governor Newsom was hopeful other carmakers would also join the deal, but that turned out to not be the case. Two vehicle trade associations, which represent a dozen car manufacturers, joined forces with Trump and called for a single set of rules on emissions nationwide.

Now, California decided to take a step forward and target the companies that don’t follow their standards.

There were warnings. California Air Resources Board Chair Mary Nichols said in May that federal tailpipe emissions rollbacks could force “an outright ban on internal combustion engines.” But now, California has taken another clear step in deciding it wants its cars to be less polluting — with or without national support, and even with or without national approval.

California’s climate path

Seen by many as a model to follow regarding climate change, California has implemented a set of measures to reduce its carbon footprint, specifically focused on developing clean energy.

The state committed to reducing its emissions by 40% by 2030, offering economic incentives for companies to pollute less. At the same time, California aims at having a zero-carbon energy matrix by 2045, seeking to decarbonize its economy by the same date.

Transportation is the most challenging sector for California, as it represents 41% of its emissions. There are 32 million vehicles in operation in the state, of which 400.000 are electric. Emissions from the sector have grown in the last four years, while the use of public transportation is declining.

The state has also been subject to the impacts of climate change. According to its climate impacts analysis, the temperature in California has increased between one and two degrees Celsius from the beginning of the twentieth century – a trend that is in line to continue.