At least 15 people were killed as a boat carrying over 50 pilgrims capsized near Pakistan's Thatta district in Sindh province on Thursday, an official said."At least 20 others have been rescued so far," Deputy Commissioner Mirza Nasir Baig said, adding that the pilgrims were on their way to an annual festival of a local saint whose shrine is located on a small island near Thatta district.According to police, the boat was overloaded and had insufficient safety measures and the accident occurred due to strong winds, Dawn online reported.Efforts were underway to rescue the remaining passengers, including women and children. Sindh Chief Minister Syed Murad Ali Shah has sought a report on the incident from the concerned authorities.