New York City, the largest U.S. public-school system, is delaying the beginning of its academic year until September 16 to give teachers more time to prepare for the return of students amid the coronavirus pandemic. Mayor Bill de Blasio announced a deal reached with labor unions representing teachers, staff, and administrators. Instruction initially was scheduled to start September 10. All students will spend the first few days learning from home online before in-person instruction begins for some students on September 21. The biggest U.S. city's plan to restart schools includes mask-wearing, staggered schedules to reduce the number of students in classrooms, supplying every school building with a nurse, and asking all staffers to get tested before school begins. The city dispatched ventilation experts to examine air flow in classrooms, and officials said they would work to make parks and streets available as outdoor teaching space if school principals were interested.