Its eastern limit is demarcated by the West Bengal Plain and the western by the Yamuna. About one-fourth of the entire population of India lives in this fertile plain. The ancient and sacred cities of Hardwar, Varanasi, Gaya and Mathura have inspired and nurtured Hindu sages, seers, philosophers, thinkers and litterateurs in this region.
This is a vast alluvial level plain. Its original site was a deep trench-like depression varying from 6 to 8 km. at the time of its origin which was later filled up by enormous sediments brought by the rivers. The fresh deposits of alluvium on the present flood plains of the rivers are called khadar’; the relatively old alluvium which is not within the reach of the fresh alluvium has beds of kankar and is termed bhangar’.
In the north the plains are fringed with almost a continuous narrow ribbon of marshy and densely forested land hardly 32 km. wide and are known as the Tarai. After independence large areas of the Tarai were reclaimed for settling refugees who came from Pakistan.
The Tarai lying to the east of the Ganga forms a continuous belt. Its width, however, decreases in Bihar because most of it lies in Nepal. Northern margin of the Tarai merges into an undulating land formed by boulders and gravel. This gravelly land falling gently towards the Tarai is called the Bhabar.
The small water channels usually sink in the Bhabar and re-appear in the Tarai either in the form of streams or springs which account for the swampy conditions of the Tarai. Since the Bhabar-Tarai belt slopes rather steeply towards the south, the rivers coming from the Himalayas flow for some distance southward before curving to the southeast or west direction to which the Ganga Plain gradually slopes.
There is a large area of this alluvial plain in the south-west which has been cut into extensive ravines (deep narrow channels) along the right bank of the Yamuna and its right-bank tributaries.
The areas badly affected by the ravines are found in Agra and Etawah districts of Uttar Pradesh and the adjoining northern parts of Morena and Bhind districts of Madhya Pradesh. Indiscriminate felling of trees and overgrazing on grasslands in the past have caused soil erosion which in turn has increased the ravines.
Ganga drains this plain which receives the Ghaghara, the Gandak and the Kosi as its left-bank tributaries and the Yamuna and the Son as its right-bank tributaries. These rivers bring from the Himalayas enormous sediments each rainy season and raise their beds and banks by depositing silt.
The banks of the rivers are often eroded at the time when the rivers are flooded by incessant rain lasting for a week or so. Once the dikes are breached, the river lets off a large quantity of water to the adjoining lowland resulting in the floods of large areas.
The depressions called chaurs in North Bihar are flooded with water. If not drained the depression do not dry and are not ready for the sowing of Rabi crops.
The Kosi in Bihar is particularly notorious for devasting floods. It is, however, recognised that though floods are useful in enriching the soil with fertile silt, they sometimes bring immediate destruction to life and property.
Tropical climate is found. Summers are hot with mean June temperature of 29.6°C in the east and 33.3°C in the west. Maximum temperature in June may be as high as 46.6°C. Winters are pleasantly mild with mean January temperature of 14.4°C in the west.
Annual rainfall is less than 102 cm, South-west of a line connecting Varanasi with Saharanpur. The annual rainfall is received during the four months from June to September. Rain though rairly reliable for crops is sometimes so abundant that rivers overflow their banks and cause devastating floods.
A little rain is however, caused by the winter depressions. After the passage of a depression, cold winds from the cold northern mountain region blow and may bring down temperature even to freezing point in this plain.
All factors favour agriculture. It has adequate rainfall in the east and unfailing supply of water from canals and wells in the relatively less rainy west, has drawn the people very close to the soil. Almost two-thirds of the total area of this region is under plough. Food crops are preferred due to pressure of population.
About 43 percent of the net area sown is irrigated. A major part of the irrigated area is restricted to the western half of the region.
Since underground water is suitable for irrigation and is available in plenty, wells are common throughout the region. About 60 percent of the net irrigated area is accounted for by the wells and tube-wells.
The various irrigation projects have been launched after independence to supply water and to reduce floods condition.
Three major irrigation canals namely the Eastern Kosi Canal, the Eastern Gandak Canal and Son Canals account for most of the area irrigated by canals in Bihar.
Most of the canal-irrigated area in Uttar Pradesh lies in the Ganga-Yamuna Doab and the Ganga- Ghaghara Doab. The Ganga-Yamuna Doab is irrigated by the Upper Ganga Canal, the Lower Ganga Canal and the Eastern Yamuna Canal. These are old canals and they irrigate a very large area.
Wheat, gram and barley are produced though the area under them decreases as we go towards the east. This region produces three-fourths of the total barley, almost one-third of the total gram and two-fifths of the total wheat produced in India. Irrigated doabs in western Uttar Pradesh in particular have a large concentration of wheat. In fact wheat is the leading crop of Uttar Pradesh.
This region produces nearly one-third of the total rapeseed and mustard and about one third of the total linseed produced in the country. In the southern Uttar Pradesh plain pulse is the leading crop and occupies more than 30 percent of the total cropped area.
Rice is the dominant crop, in the area lying to the riortii of the Ganga in Uttar Pradesh and that lying to the east of Varanasi where rainfall is more than 102 cm. during the rainy season. Maize is raised throughout the northern part of this region. This region is an important producer of maize and it accounts for nearly one-third of the total maize produced in the country.
This region is the major sugarcane producing area in India. It accounts for more than half of the total area under this crop in the country. Climatic conditions are, however, not always conducive to a vigorous growth of the cane during a period of about four months in a year.
During the months of May and June the climate is so hot and dries that the growth of cane’s retarded. Sometime the crop is damaged by the scorching heat during these months. Winter temperature after October is so low that it retards the growth of cane.
Growth of sugarcane almost stops when temperature falls below 17.7°C. Facilities of irrigation from wells and canals and virtual absence of frost further favoured the cultivation of cane. Reclaimed land in the Tarai being rich in organic matter is also important for cultivation of sugarcane.
In North Bihar a ambitious plan was launched to utilised the excess water of Kosi river which used to cause destruction to life and property. In order to tame this “river of sorrow” Kosi a barrage was constructed in 1965 near Hanumannagar (Nepal).
Embankments along both the banks of the Kosi have also been constructed to check its waywardness. These embankments were completed in 1959. They also protect about 202,000 hectares of cultivable land from the ravages of recurring floods. A power house has also been constructed on the Eastern Kosi Canal.
There is hydro electric plant for power supply. The Upper Ganga Canal has eight low waterfalls which have been harnessed for the development of power. But the power from these hydroelectric stations is used mainly for lift irrigation.
Power house at the Rihand Dam released power for industrial uses in south eastern Uttar Pradesh. In eastern Uttar Pradesh and Bihar where the Himalayas recede some kilometres further towards the north from the northern boundary of these states and remain well within Nepal power sites are negligible.
A significant number of thermal power stations have been set up to augment power supply in this densely populated area. An atomic power station has also been set up at Narora village of Bulandshahr district. The Ganga flows near the power station, it has two units of 235 mw each. There is dominance of agro-based industries.
As agricultural crops are almost evenly distributed in this region, industries based on them are generally dispersed. This is applicable especially to canesugar, pressing of oil from seeds and rice milling. Cotton and jute textiles, leather tanning, glass and engineering industries, tend to cluster in a few towns. Manufacture of canesugar is the major industry of this region.
Bagasse and firewood are generally used as fuel in these factories. Sugar factories are dispersed throughout the region, north of the Yamuna though they are concentrated in the area lying to the north of the Ganga. Bareilly, Deoria, Bijnor and Muzaffamagar districts in Uttar Pradesh and Champaran and Saran districts in North Bihar are known for the production of canesugar.
Cotton and woollen textile mills draw raw materials from other areas. Cotton textiles are centred mainly at Kanpur, Gorakhpur, Patna and a few towns in western Uttar Pradesh. Cigarettes are manufactured at Monghyr (Bihar). Tanning of leather and manufacture of leather shoes are important at Kanpur and Agra in this region.
Kanpur is the chief industrial town of this region which leads in production of manufactured goods. Supply of electricity from the Rihand Dam has encouraged the establishment of industries in Mirzapur and Varanasi districts. Firozabad in Agra district is the principal glass bangle manufacturing centre of India.
A petroleum refinery was commissioned at Barauni (Bihar) in 1965. Oil-fields near Naharkatia supply crude oil to this refinery through an 1167-km pipeline.
A plant for manufacturing heavy electrical equipment such as turbines and generators has been set up at Ranipur near Hardwar. Diesel locomotives are manufactured at Varanasi, steel structures at Naini near Allahabad and aircraft at Kanpur. A fertilizer factory went into production at Gorakhpur in 1968 and another such factory at Kanpur in 1969.
Muzaffarpur in northern Bihar manufactures miniature bulbs, chemicals, electronics goods, PVC hose pipes and measuring instruments.
The important towns of this region having more than lakhs of population and large number of industries are Kanpur, Lucknow, Varanasi, Allahabad, Agra, Patna, Dalmianagar; Gaya and Meerut.