New York City Mayor Bill de Blasio on Monday launched the nation’s broadest vaccine mandate on private businesses. Under the policy, all employers in the city must verify that in-person workers have received at least one dose of a coronavirus vaccine. If in-person workers got the two-dose Pfizer or Moderna vaccines, they must provide proof they got the second dose within 45 days.

De Blasio, who is in his last week as mayor, said he was “100 percent convinced this was the right thing to do,” The New York Times reports. Nearly 72 percent of New Yorkers were fully vaccinated as of Monday, with over 80 percent having received at least one dose of a vaccine.

It was not immediately clear what de Blasio’s successor, Mayor-elect Eric Adams, would do about the mandate. Some business leaders have said the city should give workers the option of taking regular COVID-19 tests instead of getting the shots.