Earlier, Indus Brahmaputra drainage originated from the north – eastern part of Assam and while running parallel to the Himalayas, it flowed towards the west upto sulaiman – kirthar ranges and then drained into the Arabian sea while flowing in the south Later on, as a result of geologic incidents, the north – western part of Shivalik river separated in the form of Indus river and the eastern part in the form of Brahmaputra river.
