The Department of Public Health made the announcement on Monday afternoon during a press briefing.

Health Commissioner Dr. Cheryl Bettigole said mask precautions begin Monday, but in order to provide a one-week education period for businesses, masks will be required in all indoor public spaces as of Monday, April 18.

“If we fail to act now, knowing that every previous wave of infections has been followed by a wave of hospitalizations, and then a wave of deaths, it will be too late for many of our residents,” said Bettigole, noting about 750 Philadelphia residents died in the wintertime omicron outbreak. “This is our chance to get ahead of the pandemic, to put our masks on until we have more information about the severity of this new variant.”

Starting April 18, masks will be required in all indoor public spaces, including schools and child care settings, businesses, restaurants, and government buildings.

At that time, residents will be asked to report any business not complying with the mandate to 311.

Bettigole cited a rise in COVID cases as the reason why the city is reinstating the mask requirements for indoor public spaces. Confirmed COVID-19 cases have risen more than 50% in 10 days.

The health department says the city will move to Level 2: Mask Precautions under its COVID-19 Response guidelines.

Level 2 is reached when the city meets two of the following three criteria:

• Average new cases per day are less than 225

• Hospitalizations are less than 100

• Cases have increased by more than 50% in the previous 10 days.

Under Level 2, you must wear a mask when indoors in public places.

However, there is no vaccine or testing requirement for places that serve food or drink under Level 2.

The city had lifted its indoor mask mandate and moved to the All Clear Level 1 on Wednesday, March 2. Now, 41 days later, the city is bringing it back.

The restaurant industry pushed back against the mandate, saying workers will bear the brunt of customer anger over the new rules.

“This announcement is a major blow to thousands of small businesses and other operators in the city who were hoping this spring would be the start of recovery,” said Ben Fileccia, senior director of operations at the Pennsylvania Restaurant & Lodging Association.

Councilman Allan Domb said business owners have been calling his office to express concerns.

This spring was thought to be the comeback for many businesses, including restaurants that were lucky to survive after months of closures and restrictions during the pandemic.

Reinstating a mask mandate has some concerned that customers may just decide to go elsewhere, like New Jersey or the collar counties that haven’t had any restrictions in months.

“I’m hoping I can get to the health commissioner and try to convince her we should look at other options — maybe making it strongly recommended but not required,” said Domb.

PolicyLab at Children’s Hospital of Philadelphia said Friday that while it expects some increased transmission in the northern U.S. over the next several weeks, hospital admissions have remained low and “our team advises against required masking given that hospital capacity is good.”

Bettigole said requiring people to mask up will help restaurants and other businesses stay open, while a huge new wave of COVID-19 would keep customers at home. She said hospital capacity was just one factor that went into her decision to reinstate the mandate.

“I sincerely wish we didn’t have to do this again,” Bettigole said. “But I am very worried about our vulnerable neighbors and loved ones.”

The Associated Press contributed to this report.