Even when the pandemic ends, New Yorkers will not have to give up dining by the curb.

As many of New York City’s 25,000 restaurants and bars fight to survive, Mayor Bill de Blasio extended a lifeline to them on Friday by making a popular outdoor dining program permanent.

In a crowded city where space on the streets and sidewalks is at a premium, the decision underscores how the pandemic has rapidly upended urban life.

The Open Restaurants program has allowed more than 10,300 restaurants citywide to offer outdoor dining by setting up tables on sidewalks, in streets and in other public spaces.

The outdoor dining program, introduced in June, had been scheduled to end on Oct. 31.

“Open Restaurants was a big, bold experiment in supporting a vital industry and reimagining our public space — and it worked,” Mr. de Blasio said. “As we begin a long-term recovery, we’re proud to extend and expand this effort to keep New York City the most vibrant city in the world. It’s time for a new tradition.”

The program has allowed restaurants to generate at least some income as they struggle to pay rent and keep some workers on the payroll. Indoor dining has been banned since the city was shut down by the pandemic, but is scheduled to restart next week at limited capacity.

City officials said the outdoor dining program would be expanded to allow restaurants to take over adjacent public spaces that are not being used. In addition, restaurants will be allowed to use propane heaters on the sidewalks to keep customers warm. The heaters have been prohibited for use in restaurants.

Even with the expansion of outdoor dining, a recent survey by an industry group, the New York City Hospitality Alliance, found that nearly nine out of every 10 dining establishments had not paid full rent in August and that about a third had not paid any rent.

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Citywide, about 300,000 people were employed by restaurants, bars and clubs before the pandemic, according to the Hospitality Alliance, but about half of those workers have since been laid off.

Reviving the industry, which has been hobbled by the plunge in tourists and the many office workers still working from home, will be critical to New York’s recovery.

Andrew Rigie, the executive director of the Hospitality Alliance, said the outdoor dining program was important, but much more needed to be done. He called for additional measures such as federal aid for restaurants to cover their rents, payroll and operating costs, and city and state legislation to provide rent relief and other tenant protections to restaurants.

“Making outdoor dining permanent and expanding the program is extremely important,” he said. “However, there’s not one policy solution that is going to save New York City’s restaurant industry.”

During the pandemic, Mayor de Blasio has increasingly opened some of the city’s 6,000 miles of streets for walking, biking and outdoor dining under pressure from transportation advocates as well as from many New Yorkers trapped in tiny apartments with nowhere to go. There are more than 70 miles of Open Streets, which turn blocks into car-free zones, nearly 15 miles of which allow outdoor dining.

The outdoor dining program has saved an estimated 90,000 restaurant jobs citywide, according to city officials.

Polly Trottenberg, the city transportation commissioner, said the program “has developed into one of the few bright spots in the pandemic,” calling it “a creative new vision of public space.”

Ms. Trottenberg added that her agency would work with other city agencies and officials and with the restaurant industry to develop guidelines for outdoor dining on a permanent basis.

As temperatures drop, restaurants will also have the option of enclosing their outdoor areas, but if they do, they will have to adhere to indoor dining restrictions of 25 percent capacity, the mayor said. “I think this will really help us,” Mr. de Blasio said. “We want restaurants to do well.”

Along three blocks of Arthur Avenue in the Bronx, which is famous for its Italian cuisine, 22 restaurants have created a piazza with white-tablecloth service, fresh flowers and twinkling lights that draws hundreds of people from across the region on a nice evening. A total of 48 restaurants in the area offer outdoor dining.

“It has been a lifesaver,” said Peter Madonia, the chairman of the Belmont Business Improvement District, who expects most of the restaurants to continue to offer outdoor dining in the winter and beyond.

“It was a game changer for us in terms of making sure the fabric of our community — the restaurants and retail stores — are vibrant again.”

Still, some restaurant owners and workers said Friday that outdoor dining may not be enough to save their businesses.

Kenny McPartlan, who owns Hudson Smokehouse in the South Bronx, said that there was a short window of time that outdoor dining would be comfortable before temperatures dropped and snow blanketed the streets. He said that indoor dining at limited capacity would not be enough to make ends meet. “I’ll never make money like this,” he said. “Never.”

A few doors down at Beatstro, Alfredo Angueira, a co-owner, said he’s weighing his options for how to keep customers warm in the winter, including using traditional space heaters, electric heaters or even individual “igloo” heaters for tables.

In northern Manhattan, Harlem Public was able to rehire the majority of its staff after layoffs, said Lauren Lynch, an owner of the restaurant, but she added that the city should have made outdoor dining permanent sooner. Restaurants, she said, now have to scramble to come up with a plan for winter — especially since heaters are in high demand.

“We need time and runway to make these decisions,” Ms. Lynch said. “Our hope is to not have to let go of our staff again, but we’re also very clear with them that regardless of what happens with outdoor dining, we can’t afford to keep our whole staff most likely.”

Juliana Kim contributed reporting.