Karachi
According to district officials, there were about 70 people on-board when then accident took place on Thursday evening, reports Dawn news.
Thatta Deputy Commissioner (DC) Nasir Baig said 20 people were rescued and have been hospitalised.
Rescue efforts were ongoing in coordination with military units in the area.
The passengers were mostly pilgrims were travelling to attend an annual celebration of a sufi saint.
Most of the passengers were residents of Karachi, the police added.
According to initial investigation, the capsize took place as the boat lost balance because it was overcrowded.
Visit news.dtnext.in to explore our interactive epaper!
Download the DT Next app for more exciting features!
Click here for iOS
Click here for Android