California has adopted regulation that will require zero-emissions trucks by 2045.

Some regions in California have long had a reputation for poor air quality and smog. The new regulation, the first in the US, will require half of trucks sold to be zero-emissions by 2035. The transition is expected to be 100% complete by 2045.

The California Air Resources Board touted the benefits of going zero-emissions.

“Mobile sources and the fossil fuels that power them are the largest contributors to the formation of ozone, greenhouse gas emissions, fine particulate matter (PM2.5), and toxic diesel particulate matter,” reads the statement. “In California, they are responsible for approximately 80% of smog-forming nitrogen oxide (NOx) emissions. They also represent about 50% of greenhouse gas emissions when including emissions from fuel production, and more than 95% of toxic diesel particulate matter emissions. Zero-emission vehicles have no tailpipe emissions. When compared to diesel vehicles, they are two to five times more energy efficient, reduce dependence on petroleum, and reduce GHG emissions substantially.

California’s regulation is an ambitious step, one made in the face of opposition from the automotive industry. It remains to be seen if other states will follow suit.