We're going down...

The New Moore Island in the Sunderban delta was the center of a land dispute between India and Bangladesh. Discovered in 1974 by an American satellite, the island grew substantially in size owing to silt deposits by flooding rivers. Both the nations claimed the territory and no solution was found until in 2010, when because of a specific natural cause the dispute ended in a rather dramatic way as none of the nations could claim it. What had happened?