By CBS3 Staff

PHILADELPHIA (CBS) — Philadelphia has become the first major U.S. city to reimpose an indoor mask mandate. The city said Monday it’s reached the Level 2: Mask Precautions stage of its four-tiered COVID-19 response system, and that it will reimpose the mask mandate on April 18.

Health Commissioner Dr. Cheryl Bettigole said the city will provide businesses with a one-week educational period before the mandate goes back into effect.

READ MORE: Philadelphia's Gun Violence Epidemic Continues To Have Devastating Impact On City's Youth

“We hope by having folks whenever they’re in public, indoor spaces we can get ahead of the wave and keep it from reaching a peak like we saw in January with the omicron variant,” Bettigole said. “If we can do that, we can literally save the lives of vulnerable Philadelphians. At this level of transmission, we do not believe that there is any reason to panic or enjoy any activities that we enjoy and are important to use. Our city remains open.”

Bettigole said any business that requires proof of vaccination will be exempt from the mandate.

“So as before, if an establishment — any type of establishment — chooses to be vaccine only, they can be exempt from the mask requirement, and that’s something we did before when we had the mask requirement in place,” the health commissioner said.

Under the city’s four-tiered system, to qualify for the Level 2: Mask Precautions stage, the average new daily case levels must be under 225, hospitalizations under 100 and cases up more than 50% over the previous 10 days.

The city on Monday reported 142 new cases per day, which is more than 50% higher than 10 days ago, Bettigole said.

Bettigole said the number of people hospitalized with COVID-19 remains low, at 46 people.

“Recently, we’ve been watching COVID-19 cases and hospitalizations rise in several European countries and in some places, in the U.S., and now we’re starting to see cases here in Philadelphia rise,” Bettigole said. “This looks like we may be at the start of a new COVID wave like Europe just saw. 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.”

Mayor Jim Kenney said on Twitter, “Our city remains open; we can still go about our daily lives and visit the people and places we love while masking in indoor public spaces.”

Both the U.S. Centers for Disease Control and Prevention and CHOP’s Police Lab say COVID-19 levels in Philadelphia are not enough to justify removing precautions.

“The decisions we’re making in Philly have to do with local conditions, and the CDC has been clear local conditions do matter,” Bettigole said.

Bettigole said the city is asking all businesses to start hanging up masks-required signs in their windows and having conversations with their staff about reminding people to wear their masks while indoors.

Eyewitness News spoke with members of the city’s business community, and many weren’t happy with the city’s decision.

The Pennsylvania Restaurant & Lodging Association says it’s “extremely disappointed” with the city’s decision to reinstate the indoor mask mandate. It claims the city did so without “any input from the mitigated community.”

In a statement, the PRLA said:

“Restaurant workers have suffered severe backlash when enforcing these rules in the past and, unfortunately, this time will be no different. Philadelphia restaurants have done all they can to help mitigate the spread of COVID-19 — from hosting vaccine clinics to sponsoring coronavirus test giveaways — while working to keep business in the city. It’s deflating to hear that the city plans to bring back the mask mandate, especially without having conversations with anyone from the industry about timing and approach.”

“Restaurants, caterers, event venues, and so many others in the hospitality industry have taken extreme caution to keep their guests and employees safe throughout the pandemic. These last few weeks have been no different. Similarly, Philadelphians and visitors have been confident enough in their decision-making to know when they should wear masks and when they do not. 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. While the rest of the Commonwealth has moved forward navigating life with COVID, Philadelphia has stepped back by imposing another mandate and expecting it to be enforced by businesses and their employees.”

Ben Fileccia, the senior director of operations for the PRLA, said the city’s metrics should be adjusted.

“Unfortunately, metrics came about with a different variant,” Fileccia said. “We’re dealing with a whole different issue right now, and at this point, the restaurants are still really struggling. And it’s one more obstacle for these folks to jump over to recover the industry.”

The PRLA represents more than 6,000 restaurants and hotels in Philadelphia.

“I spoke with some event and caterer professionals this morning and they’re already getting calls this morning from wedding parties and conferences trying to see if they could reschedule or move to a different county,” Fileccia said.

At Fairmount Hardware, masks were flying off the shelves again on Monday. Manager Michele Connelly says they’re trying to keep up with the constant changes.

READ MORE: Here Is Where The Pennsylvania Primary Race For The Senate Seat Stands

“On again, off again so it’s confusing for the patrons,” Connelly said. “It’s confusing for us and then you have people who are just tired of it at this point so they refuse to wear it so businesses are stuck implementing a rule that they have no control over.”

Meanwhile, others who live and work in the city say they don’t mind having to put a mask back on.

“It should be mandatory, at least in the buildings,” said Aimerey Beisembay, of University City.

As COVID-19 cases rise, some people are glad to have an indoor mask requirement coming back to the city.

“Because not everyone got their boosters,” Mia Gabdilova, of University City, said.

The new mandate doesn’t change the mask policy at Terrace Street Bakery & Cafe in Roxborough.

“We’ve never stopped,” manager Faith Brachelli said.

The manager says the bakery has kept its mask mandate for almost two years, which many customers appreciate.

“They just feel comfortable that everybody has to wear masks,” Brachelli said. “We wear masks. Everybody wears a mask until they sit down.”

Nearby at the Loft Lounge, Jeff Johnson says “the employees here all wear a mask.”

“That’s the requirement,” he said.

“They help, they could prevent — I’ve never had COVID, but I always wore a mask,” Tiffany Simpson, who works at the Loft Lounge, said.

Ali’s Wagon never dropped the masks in the first place either, saying it’s a small price to pay to stay safe.

“We are a tiny, tiny store and half our staff hasn’t had COVID, including me,” manager Jessie Menken said, “so it was sort of an easy choice as extreme as it feels when the mask mandate is gone.”

Cross Fit Two Street in Pennsport says it is just happy to be back.

“People just want to get their workouts in,” an employee said. “We don’t want to do our Zoom workouts anymore. We don’t want to go back to that. Stay in the gym and keep everyone safe.”

Fileccia says people should make their own decisions about wearing masks when out and about — not the city.

“You have to remember, we’re an island here,” Fileccia said. “Nobody in New Jersey is doing this. Nobody in the other 66 counties are doing this. So there’s lots of options for guests to go outside the city right now.”

The city says inspectors will begin going out to enforce the mandate beginning on Monday.

The renewed mask mandate will apply to all indoor public locations, including schools. Philadelphia students are currently on spring break and masks were already mandated for the week after they return. That will not be expanded.

MORE NEWS: Recent Coastal Storm Uncovers Historic 'Ghost Tracks' On Higbee Beach In Cape May, And It's Not 1st Time

CBS3’s Stephanie Stahl, Matt Petrillo and Kerri Corrado contributed to this report.