lThis region is drained by the Ganga river system in the
north and northeastern part of Bengal, the Brahmaputra
system in Assam, Meghalaya, Tripura and some parts of
Mizoram, Manipur and Nagaland. The eastern part of
Manipur, including the central plain, and Nagaland is
drained by the Chindwin river system, while the southern
part of Mizoram, by the Koladyne river system.