Boston Mayor Martin Walsh exits City Hall to begin a press conference on May 19, 2020. Photo by Jeremiah Robinson | City of Boston

Mayor Marty Walsh didn’t rule out shutting down Boston restaurants and other businesses again if the number of coronavirus cases reported in the city continues to rise.

The city’s positivity rate for the week ending Nov. 12 was 9.6 percent, up significantly from summer averages of 1.8 percent to 2.8 percent, he said at a City Hall news conference Tuesday.

“I don’t want to be standing in front of this podium three weeks from now shutting down restaurants and retail shops and businesses and sports and schools and everything that we’ve done,” Walsh said. “We don’t want to go backwards.”

He said an economic shutdown would be a last resort.

Walsh also urged people to spend Thanksgiving only with immediate members of their household.

The city will start releasing data on six key metrics twice a week in an effort to better track the spread of infections and monitor hospital capacity, he said.

Those metrics include the average number of daily cases, the community-level test positivity, the average number of daily tests administered, ICU capacity and percentage of non-surge beds occupied, overall number of beds available and the average number of emergency visits related to COVID-19, according to Marty Martinez, chief of the city’s Office Health and Human Services.

Pressure on Massachusetts hospitals is continuing to mount as the number of people hospitalized with COVID-19 steadily rises.

There were 835 people reported hospitalized Tuesday because of confirmed cases of COVID-19. That’s up from 500 a month ago.

Of those hospitalized Tuesday, nearly 160 were in intensive care units.

On Tuesday, there were 20 newly confirmed coronavirus deaths and more than 2.260 newly confirmed cases of COVID-19.

The new deaths pushed the state’s confirmed COVID-19 death toll to 10,130 and its confirmed caseload to more than 186,700.

The true number of cases is likely higher because studies suggest some people can be infected and not feel sick.

The number of probable or confirmed COVID-19 deaths reported in long-term care facilities rose to 6,610.