Police said 13 children were injured when a festival ride lost power, and they fell to the ground. The accident happened Sunday at the Oyster Festival in Norwalk, Conn., according to officials. Police said most of the children had minor injuries and were treated at the scene. Several others, however, were hurt more seriously and taken to local hospitals. Their conditions were not known late Sunday afternoon. Norwalk police called the state fire marshal’s office to investigate. The ride is made up of swings that start at the ground and rise into the air. When the ride lost power, the swings holding the children fell to the ground. The festival remained open Sunday but all rides were closed, police said.