According to the website of the China Maritime Safety Administration, the Dalian Maritime Safety Administration issued a navigation warning that from 16:00 on June 30 to 16:00 on July 7, some waters in the northern Yellow Sea of the Bohai Strait will carry out military missions and prohibit sailing.
From 5 a.m. on June 29 to 12 a.m. on July 3, military missions were carried out in some waters of the northern Yellow Sea in the Bohai Strait, and it was forbidden to sail in.
Source: Zhonghong.com