The incident took place near Marchhiya village when a speeding bus hit the auto-rickshaw carrying the pilgrims who were proceeding to Muzaffarpur, police said.
"The vehicle fell down from the bridge and all of them were injured. They were taken to government hospital at Hajipur," the official said.
Hajipur Sadar Hospital Deputy Superintendent U P Verma said, "All the injured persons are undergoing treatment and utmost care of them is being taken. Two of the injured are in serious condition at present."