New York City will become the first major US city to require proof of Covid-19 vaccination at restaurants, gyms and other businesses, Mayor Bill de Blasio said, as the nation grapples with the rapidly spreading Delta variant.

With vaccines widely available, political leaders were combating the latest surge in infections with shots and masks rather than ordering businesses to close and Americans to stay home as they did last year.

New York City's policy requires proof of at least one dose and will be enforced starting September 13. Like mask mandates and last year's stay-at-home orders, the plan will likely meet stiff resistance, Reuters reports.

“It is time for people to see vaccination as literally necessary to living a good and full and healthy life,” de Blasio, a Democrat, told a news conference.