Twenty one were killed and many others were injured when a boat carrying 50 people capsized in the Ganga river near Patna on Saturday evening.
Bihar chief minister Nitish Kumar has ordered a probe into the incident.
While a large number of passengers were able to swim to safety, more than a dozen people were still missing. According to sources, the boat that capsized was overcrowded and was returning from a kite flying festival in the late evening.
The kite flying festival was organised as part of Makar Sankranti by the state tourism department. The incident took place around 6 pm.
A team of NDRF has been deployed for the rescue operations. Patna district magistrate Sanjay Agarwal and district police officials are camping at the site.