The health department in Tennessee’s most populous county has reinstituted a face mask requirement for indoor public places such as restaurants and other businesses. The move comes Wednesday as a surge in COVID-19 cases has strained hospital resources and raised concern about schoolchildren. The health department in Shelby County, which includes Memphis, said the mask requirement will begin Friday. It applies to retail shops, grocery stores, laundries, and also bars, gyms, event venues and common areas of hotels and multi-residential buildings. A countywide mask requirement was issued in 2020 for businesses after the coronavirus pandemic took hold, but officials lifted it earlier this year.