Superintendent of police Sukesh Jain said locals who swung into action in small boats traced 18 of the missing persons.
After they were taken to Chandannagar sub divisional hospital, three of them including two women, were declared "brought dead."
The accident occurred when the passengers bound for Shyamnagar in North 24 Parganas district were waiting at the 150-feet high bamboo jetty at Telinipara for boarding a launch to cross the river.