Transportation Secretary Sean Duffy has ordered Chicago O’Hare International Airport to cut over 300 daily flights from its schedule, starting next month.

O’Hare, the largest U.S. airport by flight volume, is expected to see more than 3,080 flights on peak days this summer. With the new order, the number of flights per day will drop to 2,708 to prevent a 14.9% peak-day increase from last summer.