BOSTON (CBS) – Boston’s plastic bag ban goes back into effect Thursday.

“We lifted it temporarily in March to provide shoppers and stores more flexibility during COVID-19. But it’s important to maintain this policy as part of our climate leadership,” Mayor Marty Walsh said on Wednesday.

Customers will have to bring their own reusable bags to stores or pay 5 cents for any paper or recyclable bag they use.

Businesses that continue to use plastic face fines of $50.

“This is an ordinance we put in place in 2018 to protect our environment. Stores can only provide bags that are reusable, or recyclable, or you can use them as compost,” Walsh said. “Public health experts are clear that reusable bags are safe.”