The city of Philadelphia announced it will be requiring masks for businesses indoors and for many large outdoor gatherings.

The new mask policy goes into effect at 12:01 a.m. Thursday. In a news release issued Wednesday, the city cites the rise of the delta variant of the coronavirus, as cases and hospitalizations are spiking across the state and nationwide.

Philadelphia’s new “mask mandate” – that’s how it’s described in a city press release – comes with some exceptions. Businesses that require all employees and guests to be vaccinated will be exempt from the mask policy.

Beginning, August 12, masks are required in Philadelphia if you are indoors (unless proof of vaccination is required for entry) and at non-seated outdoor events with 1,000+ attendees.

Learn more ➡️https://t.co/OTl3ubp5iz pic.twitter.com/KDoNGJchGq

— City of Philadelphia (@PhiladelphiaGov) August 11, 2021

But masks will be required at all Philadelphia businesses, restaurants and institutions that don’t require covid-19 vaccinations for workers and guests.

All guests dining indoors and all restaurant staff will be required to wear masks, unless there’s a policy requiring vaccination. Guests will need to wear masks if they aren’t seated, eating or drinking. Some popular Philly restaurants have already said they are requiring guests dining indoors to show proof of vaccination.

Masks will also be required at all “non-seated outdoor events in Philadelphia” with more than 1,000 in attendance.

“We know that you’re probably tired of wearing a mask, but more and more people are getting infected with COVID and that’s dangerous — and even deadly,” the city’s news release states.

“We’ve said it before: wear your mask to help flatten the curve. It worked before, and it’ll work again.”

The Philadelphia Eagles issued a statement on Twitter saying fans are not required to wear a mask outdoors. But all stadium guests and staff will be required to wear a mask while visiting indoor spaces at Lincoln Financial Field. The Eagles asked all fans who aren’t vaccinated to wear a mask at all times, unless eating or drinking.

pic.twitter.com/3kVyQKAby8

— Philadelphia Eagles (@Eagles) August 11, 2021

The Eagles host the Pittsburgh Steelers in a preseason game Thursday night.

The Philadelphia School District has previously said all students and staff are required to wear masks when the new school year begins, The Philadelphia Inquirer has reported.

Pennsylvania Gov. Tom Wolf has said he will not issue a statewide requirement for masks in schools. But he said the Pennsylvania Department of Education, following federal guidance, is strongly recommending local school districts require students to wear masks.

Statewide, more than 900 people are being treated for covid-19 in hospitals, according to the Pennsylvania Department of Health. A month ago, only about 250 were hospitalized.

Philadelphia officials also announced Wednesday a new policy affecting all city employees. Beginning Sept. 1, all city employees with either have to show proof of vaccination or they will be required to wear two masks at all times while working onsite. Employees who aren’t vaccinated will be required to wear a cloth mask over a disposable or surgical mask.