California Gov. Gavin Newsom (D) announced a statewide order on Thursday mandating that Californians stay at home except for essential work and errands due to the coronavirus pandemic.

California, which is home to approximately 40 million people, will be the first state in the nation under such an order. The policy, aimed at curbing the rate of infection, goes into effect Thursday evening.

“We are confident that the people in the state of California will abide by it,” Newsom said in a Thursday news conference.

Under the stay at home, or “shelter-in-place,” policy, Californians are permitted to leave their residences for errands such as going to the grocery store or picking up a prescription at a pharmacy. Employees of businesses deemed essential are also permitted to work outside the home. And residents are still permitted to go for walks outside, so long as they practice safe social distancing.

The specific rules for Californians can be found here. There is no set end date for the policy.

Newsom said he doesn’t plan to use law enforcement to regulate the policy but urged Californians to use their “common sense” and self-regulate.

“We will have social pressure that will encourage people to do the right thing,” he said.

As of Thursday, California had more than 1,000 confirmed cases of coronavirus, and at least 19 people had died of COVID-19.

Newsom said the stay-at-home policy comes as the current rate of infection is threatening to overwhelm the state’s hospital resources. He noted the current trajectory shows the state will soon be short 10,000 hospital beds.

“If we meet this moment, we can truly bend the curve,” Newsom said. “Home isolation is not my preferred choice, I know it is not yours, but it is a necessary one.”

Several counties in the state, including most of the San Francisco Bay Area and Los Angeles, adopted similar policies earlier this week.

In a Thursday letter to President Donald Trump, Newsom requested further federal assistance as the state deals with the growing pandemic. Newsom wrote that the state projected 56% of Californians (or 25.5 million people) could become infected in a worst-case scenario, not accounting for the mitigation strategies already underway.

Newsom addressed that statistic at Thursday’s news conference.

“The numbers we put out today assume we’re just along for the ride,” he said. “We’re not. We want to manipulate those numbers down. That’s what this order is all about.”

The governor has implemented several other policies aimed at mitigating the damage of the coronavirus pandemic, including allocating as much as $1 billion in state emergency funds to address the outbreak and authorizing local governments to stop evictions as employment drops.

He’s also requested $1 billion in federal funds from congressional leaders to increase hospital capacity across the state, purchase additional medical equipment and provide more aid to vulnerable people.