The modern writers generally divide India’s landscape into four well-marked units.
A) The Himalayas
In the northern India lay the greatest and the highest mountains called the Himalayas. In the ancient times, they were called as Himavant meaning the “abode of the snow”. This snowy wall runs across the north India and is about 2500 kilometres in length. It stretched from Assam in the east to Afghanistan in the west. Its eastern branches include the Khasi, Lushai, Patkoi and Jaintia hills and extend upto the Bay of Bengal. These areas are covered with dense forests. Being of considerable heights, they separate Burma from India. The western branches of the Himalayas extend from North-west India to the Arabian Sea. These branches are known as Sulaiman and Kirthar Ranges. They separate India from Afghanistan and are not as high as the hills on the eastern side.
The Mountain Passes: A mountain pass is generally a narrow opening pierced by a river for its way to the plains. In the Himalayas, there are many large and small passes.
There are important passes in the Sulaiman ranges which connect India with Afghanistan. The Khyber is a low lying pass in the broad valley of the river Kabul. This pass commands the direct route from Kabul to Peshawar. It was the junction or meeting point of ancient trade routes. It was also through this gateway that most of the foreign traders and invaders entered India. The Kurram, Tochi and Gomal passes connected Derajat and Bannu with Central Afghanistan. The Bolan pass connected India with Kandhar. It was the centre of the caravan routes to Siestan and Persia.
B) The Indo-Gangetic Plain
The other natural heritage of India is the Indo-Gangetic plain. It is about 2000 miles long and on the average, 200 miles broad. It lies between the foot of the Himalayas and the Arabian Sea in the west and the Bay of Bengal in the east. This plain is made of silt brought by the three great Himalayan rivers— Brahmaputra, Ganga and the Indus and their tributaries. These rivers have a regular flow of water from the Himalayan snow and some of their tributaries are navigable in the plains from the Bay of Bengal to Agra and from the Arabian Sea to Lahore. In fact, before the introduction of the railways, these river systems used to carry a large volume of trade and traffic.
The Indo-Gangetic Plain is divided into three unequal compartments. The Santhal Parganas cut Bengal from the main Gangetic plain. On the west, a little beyond Delhi, Rajputana desert separates the Indus basin from the Gangetic plains. The Gangetic plain is the most prosperous and populous region of India. Its people are handsome, healthy and mostly the descendants of the Aryans.
The Aravali mountain hills divide the Indo-Gangetic plain into two parts.
The Eastern Part of the Gangetic Plain: The territories lying in the east of the Aravali hills are called the Eastern Gangetic They contain Ganges, Yamuna, Chambal, Ghaghara and Brahmaputra. The biggest cities of India which were once the capitals of great empires and centres of culture and civilization are situated in this region. These important towns are Allahabad, Banaras, Lucknow, Kanpur, Pataliputra (Patna), Bhopal, Senchi, Calcutta (Kolkata) and Dacca. These territories have abundant rainfall and the land is very fertile. The chief agricultural products of this region are rice, wheat, sugarcane, tobacco etc. The Gangetic plains were also the centres of art, literature and religious movements.
The Western Part of the Gangetic Plain: The south-western ends of the Indo-Gangetic plains are called the plains of the Indus. Important rivers like Sindh, Jhelum, Chenab, Ravi, Beas and Satluj flow through this region. The important towns in this region are Lahore, Multan, Gujranwala, Amritsar, Jalandhar, Ludhiana, Patiala, Ambala, Panipat, Delhi, Bikaner, Jaipur, Jodhpur etc. This region has comparatively low rainfall. But the streams, canals and wells provide enough water for irrigation of land. Large territories of Rajasthan and Sindh are deserts but the plains of the Punjab are fertile. The Jndus plains made less progress in art and literature as compared to the Gangetic plains. The density of population is also comparatively low in the plains of the Indus.
C) The Deccan Plateau (The South Land)
The Deccan is a triangular table-land rising abruptly in the west and sloping away towards the east. In this area, the chief rivers are, the Narmada, the Tapti, the Godavari and the Krishna. All the important rivers, with the exception of the Narmada and Tapti, flow westwards and fall into Arabian Sea. All the others flow into the Bay of Bengal. In the rainy season, all these rivers are often in flood and are not of much service as a means of irrigation. On the other hand, the rivers of the North viz, the Indus and the Ganges and their tributaries derive water from the Himalaya’s snow-fields and have a regular flow of water.
The Deccan table-land is separated from the North India by a number of natural barriers. The Vindhyas and the Satpuras with their outlying ranges form an important barrier towards the north. The valleys of the Narmada and Tapti rivers as well as the dense jungles lying south of Chhota Nagpur region constitute other barriers which were difficult to cross in ancient times. These barriers resulted in a tendency to keep the history of the rest of India apart from that of Deccan. The two—North and the South, had seldom been combined in one political and cultural bond. Most powerful Indian rulers like Ashoka, Samudragupta, Ala-ud-Din Khalji, Muhammad Tughlaq and even Aurangzeb could not succeed completely in subduing the Deccan.
D) The Coastlines
The Central table-land of Deccan is made of hard granite rock covered here and there with lava soil. This extends from the Vindhyas and Satpura mountains in the north to the Indian Ocean in the south. A greater p1rt of area between the Bay of Bengal and Arabian Sea is included in this region.
1) The Eastern Ghats: The area between the Central Plateau and the Bay of Bengal is called the Eastern Ghats. The region of the Eastern coast is formed by Godavari, Mahanadi, Krishna etc. These have enriched the soil of the Eastern Coast. The North-east winter monsoons give the area rainfall in winter and enable good cultivation.
2) Western Ghats: The narrow strip of land lying between the western heights of the Central and the Arabian Sea is called the Western Ghats. It is narrow at many places, not more than twenty miles wide. This has a rich soil and is always green with rice fields and coconut plants. The Narmada and the Tapti rivers in the north connect the Central Region with the Central Plateau.
3) The Southern end of the Peninsula: In the south of the western height of the peninsula lies the famous Paighat or “Gap of Coimbatore”. This pass connects the Malabar coast with Karnataka. This, Tamil country is watered by the Perinar and Kaveri rivers and is one of the most densely populated areas in the far south.