By Ian Duncan and Michael Laris March 17, 2020 at 8:17 p.m. EDT The air traffic control tower at Chicago’s Midway airport was temporarily closed Tuesday after several technicians tested positive for the novel coronavirus, the Federal Aviation Administration said. The agency said operations would continue at reduced levels. A ground stop — an order halting flights from taking off from or departing for the airport — was issued just after 5 p.m. Tuesday but was lifted soon after. “The air traffic system is a resilient system with multiple backups in place,” the agency said in a statement. “This shift is a regular execution of a long-standing contingency plan to ensure continued operations. Each facility across the country has a similar plan that has been updated and tested