At least 46 people, including 37 children, drowned in separate incidents across the state's 15 districts, a statement from Bihar's disaster management department said. Authorities have recovered 43 bodies so far, and the three missing people are presumed to be dead.
During the annual festival, mothers fast for 24 hours for the well-being of their children. The women are sometimes accompanied by their children when they visit rivers and ponds for cleansing rituals. The festival concluded Thursday.
The state government has announced a compensation of 400,000 rupees ($4,784) for the families of each of the dead.
Deadly accidents like drownings and stampedes during religious festivals are common in India.
In July, at least 121 people were killed after severe overcrowding and a lack of exits contributed to a stampede at a religious festival in northern India.