Attendance at Tanglewood will be capped at 9,000 this summer, in accordance with regulations approved Thursday by the Tri-Town Health Department.

The move clears the way for the Boston Symphony Orchestra to double the previous limit of 4,500 combined in the open-air Koussevitzky Music Shed and on the lawn. Additional tickets are expected to be put on sale, with a total of 2,500 seats available in the Shed and 6,500 on the lawn.

During a brief public hearing Thursday morning, Tri-Town Executive Director James Wilusz said the regulation was crafted with the involvement and endorsement of town counsels for Lenox and Stockbridge. It was adopted in response to Gov. Charlie Baker having lifted most pandemic restrictions as of Saturday.

The 9,000 cap represents 50 percent of Tanglewood’s capacity. Some scheduled performances, including those featuring Yo-Yo Ma and John Williams, had been sold out because of the previous limit of 4,500 tickets.

Tanglewood, which mostly is in Stockbridge, except for a small portion in Lenox, has a crowd limit of 18,000, which typically is reached when James Taylor performs. His Tanglewood date is set for Aug. 31, but it’s not known whether any additional tickets will be made available, since an estimated 15,000 were already sold for his postponed July 4, 2020, which will be honored for this summer’s show.