Wetland ecosystem of which most are located in northeast Bangladesh. The typical form is that of a bowl or saucer-shaped depression and the core haor area is surrounded by hills of the Indian states of Meghalaya to the north, Tripura and Mizoram to the south, and Assam and Manipur to the east. The area is known locally as the 'Haor' or 'Sylhet' basin and floods extensively each year during the annual monsoons.