SAN JUAN, Puerto Rico—Puerto Rico’s governor on Monday announced new restrictions to fight a rise in COVID-19 cases, including closing certain private businesses and banning alcohol sales after midnight. Social activities such as concerts, weddings, birthdays, and anniversaries also will be banned during those hours, and people will be required to wear masks outside if there is a crowd of 50 or more. In addition, elective surgeries that require the use of intensive care units will be prohibited. The measures will be in effect between Sept. 2 and Sept. 23, and affect businesses including restaurants and theaters. “We’re on the right track, but there was no alternative,” Gov. Pedro Pierluisi said, referring to a recent spike in cases and deaths blamed largely on the Delta variant. The announcement comes on the same day that people in the U.S. territory are required to start showing proof of vaccination to enter gyms, …