After a gap of over 40 years, the hilsa will be able to swim down the Ganga all the way up to Allahabad this monsoon. The migration of Hilsa till Allahabad had been possible till a barrage was built across the Ganges at Farakka in Bengal in the 70s. This lock has now been redesigned to ensure smooth and safe migration of the hilsa shoal during the three mating seasons, particularly during monsoon.