(1) The Arunachal Himalayas extend from the east of Bhutan Himalayas upto the Diphu pass in the east, Kangtu and Namcha Barwa being important mountain, peakas. Important rivers are Kameng, Subansiri, Dihang, Dibang and Lohit.
(2) Eastern hills and mountains known by different names, e.g. In the north they are known as Patkai Bum, Nagahills, the Maripur hills and in south as Mizoor Lushai hills.
There is strategic importance of the region because it is surrounded by China to the north, Myanmar to the east and Bangladesh to the south. Assam is connected with the rest of India only by a narrow strip of level land called the West Bengal Duars. It is situated at the foot of the Himalayas.
There are dense, evergreen and deciduous forests which grow on large continuous stretches of Arunachal Pradesh, Mizoram, Tripura and some parts of Assam. The terrain is highly rugged.
There is production of sal and firewood in the Lower Assam Valley and in the neighbouring hills. In the Upper Assam Valley and the river valleys in the adjoining hilly areas there are tropical’ evergreen forests which supply timber for constructional purposes and for making furniture. Bamboo grows in profusion at many places of this region.
About 70 percent of people are engaged in agriculture in this region. Assam State comprising most of the Brahmaputra Valley and covering only 31 percent of the total area of this region is the leading rice, tea, jute, rapeseed and mustard producing area of North-Eastern India.
This state accounts for nearly 75 percent of the total cropped area of all the states of this region. Rice is the dominant crop everywhere. Most of the area under rice is found in Assam. Tea, jute and Mesta are other important crops. This State produces about 55 percent of total tea and 14 per cent of total jute produced in country.
Jute is also produced in Meghalaya and Tripura. Rapeseed and mustard are significant crops of Assam State. Banana and potato are also raised in some parts of this region. Arunachal Pradesh, Nagaland and Mizoram produce mainly rice.
This is a primitive type of subsistence agriculture practised in areas covered with tropical rain forests. There is the leaching of soils due to heavy rainfall of 250 cm. As a result, soil loses its fertility soon after two or three years of crop cultivation. The people are forced to make a difficult living by thriving on shifting cultivation.
These patches of virgin forest whose soil is rich in humus are selected for clearing. In the dry season, trees are felled and set on fire. The ash of the burnt trees and other vegetation improves upon the fertility of the soil. The cleared patch of land for crop cultivation called ‘jhum’ is rarely ploughed. Seeds are placed in shallow holes dug up with a hoe just before the rains.
Maize, pulse, sweet potato and mustard are produced in addition to rice. After growing crops for two or three years, the soil is degenerated and the ‘jhum’ is abandoned. Then another patch of forest is cleared for raising crops. In such areas abandoned jhums’ are again cleared but after they have been left fallow for a period of 5 to 10 years.
They are in plenty. Hydro-electric power can be developed at some sites in Meghalaya and elsewhere. Natural gas, petroleum and coal are also abundant for the development of electricity.
The Umtru Hydro-electric Project (Meghalaya) with an installed capacity of 11,000 kW. Supplies electricity to Meghalaya and the Lower Assam Valley. Electricity generated at Gauhati and Namrup are based on natural gas supplied by the local petroleum refinery.
There are tribal people having distinctive culture. They exhibit a great diversity, not found in any other area of the size of this region in their language, dress, religion and stage of cultural advancement. Ancestor-worship and belief in animism are common among some tribes of this region.
There is a contrast in physical diversity. The highly rugged and towering Assam Himalayas stretch in east-west direction in the north. The Patkai, Naga, Manipur and Mizo hills extend in the north-south direction in the east. The Brahmaputra or the Assam Valley lies South of Himalaya.
The southern margin of this valley is flanked with the Garo, Khasi, Jaintia and Mikir hills, collectively known as the Meghalaya Hills. This area is divided in the following geographic regions: (a) The Assam Valley (b) The Meghalaya Hills or Shillong Plateau (c) The Eastern Highlands (d) The Assam Himalayas.