INDIA IS A COUNTRY of great diversity with a wide range of landform
types, including major mountain ranges, deserts, rich agricultural
plains, and hilly jungle regions. Indeed, the term Indian
subcontinent aptly describes the enormous extent of the earth's
surface that India occupies, and any attempt to generalize about its
physiography is inaccurate. Diversity is also evident in the
geographical distribution of India's ethnic and linguistic groups. In
ancient times, the major river valleys of the Indo-Gangetic Plain of
South Asia were among the great cradles of civilization in Asia, as were
the valleys of the Tigris and Euphrates rivers in West Asia and the
Huang He (Yellow River) in East Asia. As a result of thousands of years
of cultural and political expansion and amalgamation, contemporary India
has come to include many different natural and cultural regions.
The Himalayas (and the nations of Nepal and Bhutan) form India's
northern frontier with China. Pakistan borders India to the west and
Bangladesh (formerly East Pakistan) to the east. Although both were
formerly part of the British Indian Empire, India and Pakistan became
separate countries in 1947 and East Pakistan became independent
Bangladesh in 1971. The boundaries of the Indian polity are not fully
demarcated because of regional ethnic and political disputes and are the
source of occasional tensions.
When the 1991 national census was taken, India's population was
approximately 846.3 million. The annual population growth rate from 1981
to 1991 was 2 percent. Accounting for only 2.4 percent of the world's
landmass, India is home to 16 percent of the world's population. Every
sixth person in the world in the early 1990s was an Indian. It is
generally assumed that India's population will surpass the 1 billion
mark some time before the next census in 2001. In July 1995, the
population was estimated at 936.5 million.
Some 38 percent of all Indians were officially listed as living below
the poverty line in fiscal year (FY--see Glossary) 1991. This number
represented an increase from the low mark of 26 percent in FY 1989, but
the rise was believed to be only temporary by some observers. Although
government-sponsored health clinics are widely available in the
mid-1990s, their emphasis is on curative techniques rather than
preventive medicine. However, the lack of such basic amenities as safe,
potable water for much of the population is indicative of the severity
of health problems. This situation has traditionally led most Indians to
have large families as their only form of insurance against sickness and
for their care in old age. Although family planning programs are
becoming integrated with the programs of urban and rural health clinics,
no official birth control programs have widespread support. The severity
of the acquired immune deficiency syndrome (AIDS) epidemic in India has
become increasingly apparent to health specialists, but local awareness
of the causes of and ways to prevent the spread of AIDS is growing
slowly.
Although many public schools are inadequate, improvements to the
education system overall have been substantial since 1947. In the
mid-1990s, however, only about 50 percent of children between the ages
of six and fourteen are enrolled in schools. The goal of compulsory and
free primary and middle school education is embodied in the Indian
constitution but has been elusive. The National Policy on Education of
1986 sought to institutionalize universal primary education by setting
1990 as a target date for the education of all children up to eleven
years of age. The ability of India's education system to meet this goal
has been constrained by lack of adequate financial resources. Important
achievements have been made, however, with implementation of the
nonformal education system and adult education programs. Whereas public
education is generally below standard, education standards in private
schools are very high. There also are high standards among the elite
institutions in the higher education system.
India - Geography
Principal Regions
India's total land mass is 2,973,190 square kilometers and is divided
into three main geological regions: the Indo-Gangetic Plain, the
Himalayas, and the Peninsula region (see fig. 5). The Indo-Gangetic
Plain and those portions of the Himalayas within India are collectively
known as North India. South India consists of the peninsular region,
often termed simply the Peninsula. On the basis of its physiography,
India is divided into ten regions: the Indo-Gangetic Plain, the northern
mountains of the Himalayas, the Central Highlands, the Deccan or
Peninsular Plateau, the East Coast (Coromandel Coast in the south), the
West Coast (Konkan, Kankara, and Malabar coasts), the Great Indian
Desert (a geographic feature known as the Thar Desert in Pakistan) and
the Rann of Kutch, the valley of the Brahmaputra in Assam, the
northeastern hill ranges surrounding the Assam Valley, and the islands
of the Arabian Sea and the Bay of Bengal.
Indo-Gangetic Plain
In social and economic terms, the Indo-Gangetic Plain is the most
important region of India. The plain is a great alluvial crescent
stretching from the Indus River system in Pakistan to the Punjab Plain
(in both Pakistan and India) and the Haryana Plain to the delta of the
Ganga (or Ganges) in Bangladesh (where it is called the Padma).
Topographically the plain is homogeneous, with only floodplain bluffs
and other related features of river erosion and changes in river
channels forming important natural features.
Two narrow terrain belts, collectively known as the Terai, constitute
the northern boundary of the Indo-Gangetic Plain. Where the foothills of
the Himalayas encounter the plain, small hills known locally as ghar
(meaning house in Hindi) have been formed by coarse sands and pebbles
deposited by mountain streams. Groundwater from these areas flows on the
surface where the plains begin and converts large areas along the rivers
into swamps. The southern boundary of the plain begins along the edge of
the Great Indian Desert in the state of Rajasthan and continues east
along the base of the hills of the Central Highlands to the Bay of
Bengal (see fig. 1). The hills, varying in elevation from 300 to 1,200
meters, lie on a general east-west axis. The Central Highlands are
divided into northern and southern parts. The northern part is centered
on the Aravalli Range of eastern Rajasthan. In the northern part of the
state of Madhya Pradesh, the Malwa Plateau comprises the southern part
of the Central Highlands and merges with the Vindhya Range to the south.
The main rivers that flow through the southern part of the plain--the
Narmada, the Tapti, and the Mahanadi--delineate North India from South
India (see Rivers, this ch.).
Some geographers subdivide the Indo-Gangetic Plain into three parts:
the Indus Valley (mostly in Pakistan), the Punjab (divided between India
and Pakistan) and Haryana plains, and the middle and lower Ganga. These
regional distinctions are based primarily on the availability of water.
By another definition, the Indo-Gangetic Plain is divided into two
drainage basins by the Delhi Ridge; the western part consists of the
Punjab Plain and the Haryana Plain, and the eastern part consists of the
Ganga-Brahmaputra drainage systems. This divide is only 300 meters above
sea level, contributing to the perception that the Indo-Gangetic Plain
appears to be continuous between the two drainage basins. The Punjab
Plain is centered in the land between five rivers: the Jhelum, the
Chenab, the Ravi, the Beas, and the Sutlej. (The name Punjab
comes from the Sanskrit pancha ab , meaning five waters or
rivers.)
Both the Punjab and Haryana plains are irrigated with water from the
Ravi, Beas, and Sutlej rivers. The irrigation projects emanating from
these rivers have led to a decrease in the flow of water reaching the
lower drainage areas in the state of Punjab in India and the Indus
Valley in Pakistan. The benefits that increased irrigation has brought
to farmers in the state of Haryana are controversial in light of the
effects that irrigation has had on agricultural life in the Punjab areas
of both India and Pakistan.
The middle Ganga extends from the Yamuna River in the west to the
state of West Bengal in the east. The lower Ganga and the Assam Valley
are more lush and verdant than the middle Ganga. The lower Ganga is
centered in West Bengal from which it flows into Bangladesh and, after
joining the Jamuna (as the lower reaches of the Brahmaputra are known in
Bangladesh), forms the delta of the Ganga. The Brahmaputra (meaning son
of Brahma) rises in Tibet (China's Xizang Autonomous Region) as the
Yarlung Zangbo River, flows through Arunachal Pradesh and Assam, and
then crosses into Bangladesh. Average annual rainfall increases moving
west to east from approximately 600 millimeters in the Punjab Plain to
1,500 millimeters around the lower Ganga and Brahmaputra.
The Himalayas
The Himalayas, the highest mountain range in the world, extend along
the northern frontiers of Pakistan, India, Nepal, Bhutan, and Burma.
They were formed geologically as a result of the collision of the Indian
subcontinent with Asia. This process of plate tectonics is ongoing, and
the gradual northward drift of the Indian subcontinent still causes
earthquakes (see Earthquakes, this ch.). Lesser ranges jut southward
from the main body of the Himalayas at both the eastern and western
ends. The Himalayan system, about 2,400 kilometers in length and varying
in width from 240 to 330 kilometers, is made up of three parallel
ranges--the Greater Himalayas, the Lesser Himalayas, and the Outer
Himalayas--sometimes collectively called the Great Himalayan Range. The
Greater Himalayas, or northern range, average approximately 6,000 meters
in height and contain the three highest mountains on earth: Mount
Everest (8,796 meters) on the China-Nepal border; K2 (8,611 meters, also
known as Mount Godwin-Austen, and in China as Qogir Feng) in an area
claimed by India, Pakistan, and China; and Kanchenjunga (8,598 meters)
on the India-Nepal border. Many major mountains are located entirely
within India, such as Nanda Devi (7,817 meters) in the state of Uttar
Pradesh. The snow line averages 4,500 to 6,000 meters on the southern
side of the Greater Himalayas and 5,500 to 6,000 on the northern side.
Because of climatic conditions, the snow line in the eastern Himalayas
averages 4,300 meters, while in the western Himalayas it averages 5,800
meters.
The Lesser Himalayas, located in northwestern India in the states of
Himachal Pradesh and Uttar Pradesh, in north-central India in the state
of Sikkim, and in northeastern India in the state of Arunachal Pradesh,
range from 1,500 to 5,000 meters in height. Located in the Lesser
Himalayas are the hill stations of Shimla (Simla) and Darjiling
(Darjeeling). During the colonial period, these and other hill stations
were used by the British as summer retreats to escape the intense heat
of the plains. It is in this transitional vegetation zone that the
contrasts between the bare southern slopes and the forested northern
slopes become most noticeable.
The Outer or Southern Himalayas, averaging 900 to 1,200 meters in
elevation, lie between the Lesser Himalayas and the Indo-Gangetic Plain.
In Himachal Pradesh and Uttar Pradesh, this southernmost range is often
referred to as the Siwalik Hills. It is possible to identify a fourth,
and northernmost range, known as the Trans-Himalaya. This range is
located entirely on the Qinghai-Xizang Plateau, north of the great
west-to-east trending valley of the Yarlung Zangbo River. Although the
Trans-Himalaya Range is divided from the Great Himalayan Range for most
of its length, it merges with the Great Himalayan Range in the western
section--the Karakoram Range--where India, Pakistan, and China meet.
The southern slopes of each of the Himalayan ranges are too steep to
accumulate snow or support much tree life; the northern slopes generally
are forested below the snow line. Between the ranges are extensive high
plateaus, deep gorges, and fertile valleys, such as the vales of Kashmir
and Kulu. The Himalayas serve a very important purpose. They provide a
physical screen within which the monsoon system operates and are the
source of the great river systems that water the alluvial plains below
(see Climate, this ch.). As a result of erosion, the rivers coming from
the mountains carry vast quantities of silt that enrich the plains.
The area of northeastern India adjacent to Burma and Bangladesh
consists of numerous hill tracts, averaging between 1,000 and 2,000
meters in elevation, that are not associated with the eastern part of
the Himalayas in Arunachal Pradesh. The Naga Hills, rising to heights of
more than 3,000 meters, form the watershed between India and Burma. The
Mizo Hills are the southern part of the northeastern ranges in India.
The Garo, Khasi, and Jaintia hills are centered in the state of
Meghalaya and, isolated from the northeastern ranges, divide the Assam
Valley from Bangladesh to the south and west.
The Peninsula
The Peninsula proper is an old, geologically stable region with an
average elevation between 300 and 1,800 meters. The Vindhya Range
constitutes the main dividing line between the geological regions of the
Indo-Gangetic Plain and the Peninsula. This range lies north of the
Narmada River, and when viewed from there, it is possible to discern the
prominent escarpments that rise between 800 and 1,400 meters. The
Vindhya Range defines the north-central and northwestern boundary of the
Peninsula, and the Chota Nagpur Plateau of southern Bihar forms the
northeastern boundary. The uplifting of the plateau of the central
Peninsula and its eastward tilt formed the Western Ghats, a line of
hills running from the Tapti River south to the tip of the Peninsula.
The Eastern Ghats mark the eastern end of the plateau; they begin in the
hills of the Mahanadi River basin and converge with the Western Ghats at
the Peninsula's southern tip.
The interior of the Peninsula, south of the Narmada River, often
termed the Deccan Plateau or simply the Deccan (from the Sanskrit daksina
, meaning south), is a series of plateaus topped by rolling hills and
intersected by many rivers. The plateau averages roughly 300 to 750
meters in elevation. Its major rivers--the Godavari, the Krishna, and
the Kaveri--rise in the Western Ghats and flow eastward into the Bay of
Bengal.
The coastal plain borders the plateau. On the northwestern side, it
is characterized by tidal marshes, drowned valleys, and estuaries; and
in the south by lagoons, marshes, and beach ridges. Coastal plains on
the eastern side are wider than those in the west; they are focused on
large river deltas that serve as the centers of human settlement.
Offshore Islands
India's offshore islands, constituting roughly one-quarter of 1
percent of the nation's territory, lie in two groups located off the
east and west coasts. The northernmost point of the union territory of
the Andaman and Nicobar Islands lies 1,100 kilometers southeast of
Calcutta. Situated in the Bay of Bengal in a chain stretching some 800
kilometers, the Andaman Islands comprise 204 islands and islets, and
their topography is characterized by hills and narrow valleys. Although
their location is tropical, the climate of the islands is tempered by
sea breezes; rainfall is irregular. The Nicobar Islands, which are south
of the Andaman Islands, comprise nineteen islands, some with flat,
coral-covered surfaces and others with hills. The islands have a nearly
equatorial climate, heavy rainfall, and high temperatures. The union
territory of Lakshadweep (the name means 100,000 islands) in the Arabian
Sea, comprises--from north to south--the Amindivi, Laccadive, Cannanore,
and Minicoy islands. The islands, only ten of which are inhabited, are
spread throughout an area of approximately 77,000 square kilometers. The
islands are low-lying coral-based formations capable of limited
cultivation.
<>Coasts and Borders
India has 7,000 kilometers of seacoast and shares 14,000 kilometers
of land frontier with six nations: Pakistan, China, Nepal, Bhutan,
Bangladesh, and Burma. India claims a twelve-nautical-mile territorial
sea and an exclusive economic zone of 200 nautical miles. The
territorial seas total 314,400 square kilometers.
In the mid-1990s, India had boundary disagreements with Pakistan,
China, and Bangladesh; border distances are therefore approximations.
The partition of India in 1947 established two India-Pakistan frontiers:
one on the west and one on the east (East Pakistan became Bangladesh in
1971).
Disputes over the state of Jammu and Kashmir led to hostilities
between India and Pakistan in 1947. The January 1, 1949, cease-fire
arranged by the United Nations (UN) divided control of Kashmir. India
controls Jammu, the Vale of Kashmir, and the capital, Srinagar, while
Pakistan controls the mountainous area to the northwest. Neither side
accepts a divided Kashmir as a permanent solution. India regards as
illegal the 1963 China-Pakistan border agreement, which ceded to China a
portion of Pakistani-controlled Kashmir. The two sides also dispute the
Siachen Glacier near the Karakoram Pass. Further India-Pakistan
hostilities in the 1965 war were settled through the Soviet-brokered
Tashkent Declaration.
In 1968 an international tribunal settled the dispute over the Rann
of Kutch, a region of salt flats that is submerged for six months of the
year in the state of Gujarat. The following year, a new border was
demarcated that recognized Pakistan's claim to about 10 percent of the
area.
In 1992 India completed fencing most of the 547-kilometer-long
section of the boundary between the Indian state of Punjab and the
Pakistani province of Punjab. This measure was undertaken because of the
continuing unrest in the region caused by both ethnic and religious
disputes among the local Indian population and infiltrators from both
sides of the frontier. The more rugged terrain north of Punjab along the
entire cease-fire line between India and Pakistan in Jammu and Kashmir
continues to be subject to infiltration and local strife (see Political
Issues, ch. 8; South Asia, ch. 9; Insurgent Movements and External
Subversion, ch. 10).
The 2,000-kilometer-long border with China has eastern, central, and
western sections. In the western section, the border regions of Jammu
and Kashmir have been the scene of conflicting claims since the
nineteenth century. China has not accepted India's definitions of the
boundary and has carried out defense and economic activities in parts of
eastern Kashmir since the 1950s. In the 1960s, China finished
construction of a motor road across Aksai Chin (a region under dispute
between India and China), the main transportation route linking China's
Xinjiang-Uygur Autonomous Region and Tibet.
In the eastern section, the China-India boundary follows the McMahon
Line laid down in 1914 by Sir Arthur Henry McMahon, the British
plenipotentiary to a conference of Indian, British, and Chinese
representatives at Simla (now known as Shimla, Himachal Pradesh). The
Simla Convention, as the agreement is known, set the boundary between
India and Tibet. Although the British and Tibetan representatives signed
the agreement on July 3, 1914, the Chinese delegate declined to sign.
The line agreed to by Britain and Tibet generally follows the crest of
the eastern Himalayas from Bhutan to Burma. It serves as a legal
boundary, although the Chinese have never formally accepted it. China
continued to claim roughly the entire area of Arunachal Pradesh south of
the McMahon Line in the early 1990s. In 1962 China and India fought a
brief border war in this region, and China occupied certain areas south
of the line for several months (see Nehru's Legacy, ch 1; The Experience
of Wars, ch. 10). India and China took a major step toward resolving
their border disputes in 1981 by opening negotiations on the issue.
Agreements and talks held in 1993 and 1995 eased tensions along the
India-China border (see China, ch. 9). Sikkim, which became an Indian
state in 1975, forms the small central section of India's northern
border and lies between Nepal and Bhutan.
India's border with Bangladesh is essentially the same as it was
before East Pakistan became Bangladesh in 1971. Some minor disputes
continued to occur over the size and number of the numerous enclaves
each country had on either side of the border. These enclaves were
established during the period from 1661 to 1712 during fighting between
the Mughal Empire and the principality of Cooch Behar. This complex
pattern of enclaves was preserved by the British administration and
passed on intact to India and Pakistan.
The 1,300-kilometer frontier with Burma has been delimited but not
completely demarcated. On March 10, 1967, the Indian and Burmese
governments signed a bilateral treaty delimiting the boundary in detail.
India also has a maritime boundary with Burma in the area of the
northern Andaman Islands and Burma's Coco Islands in the Bay of Bengal.
India's borders with Nepal and Bhutan have remained unchanged since the
days of British rule. In 1977 India signed an accord with Indonesia
demarcating the entire maritime boundary between the two countries. One
year earlier, a similar accord was signed with the Maldives.
India - Rivers
The country's rivers are classified as Himalayan, peninsular,
coastal, and inland-drainage basin rivers. Himalayan rivers are snow fed
and maintain a high to medium rate of flow throughout the year. The
heavy annual average rainfall levels in the Himalayan catchment areas
further add to their rates of flow. During the monsoon months of June to
September, the catchment areas are prone to flooding. The volume of the
rain-fed peninsular rivers also increases. Coastal streams, especially
in the west, are short and episodic. Rivers of the inland system,
centered in western Rajasthan state, are few and frequently disappear in
years of scant rainfall. The majority of the South Asia's major rivers
flow through broad, shallow valleys and drain into the Bay of Bengal.
The Ganga River basin, India's largest, includes approximately 25
percent of the nation's area; it is bounded by the Himalayas in the
north and the Vindhya Range to the south. The Ganga has its source in
the glaciers of the Greater Himalayas, which form the frontier between
India and Tibet in northwestern Uttar Pradesh. Many Indians believe that
the legendary source of the Ganga, and several other important Asian
rivers, lies in the sacred Mapam Yumco Lake (known to the Indians as
Manasarowar Lake) of western Tibet located approximately 75 kilometers
northeast of the India-China-Nepal tripoint. In the northern part of the
Ganga River basin, practically all of the tributaries of the Ganga are
perennial streams. However, in the southern part, located in the states
of Rajasthan and Madhya Pradesh, many of the tributaries are not
perennial.
The Brahmaputra has the greatest volume of water of all the rivers in
India because of heavy annual rainfall levels in its catchment basin. At
Dibrugarh the annual rainfall averages 2,800 millimeters, and at
Shillong it averages 2,430 millimeters. Rising in Tibet, the Brahmaputra
flows south into Arunachal Pradesh after breaking through the Great
Himalayan Range and dropping rapidly in elevation. It continues to fall
through gorges impassable by man in Arunachal Pradesh until finally
entering the Assam Valley where it meanders westward on its way to
joining the Ganga in Bangladesh.
The Mahanadi, rising in the state of Madhya Pradesh, is an important
river in the state of Orissa. In the upper drainage basin of the
Mahanadi, which is centered on the Chhattisgarh Plain, periodic droughts
contrast with the situation in the delta region where floods may damage
the crops in what is known as the rice bowl of Orissa. Hirakud Dam,
constructed in the middle reaches of the Mahanadi, has helped in
alleviating these adverse effects by creating a reservoir.
The source of the Godavari is northeast of Bombay (Mumbai in the
local Marathi language) in the state of Maharashtra, and the river
follows a southeasterly course for 1,400 kilometers to its mouth on the
Andhra Pradesh coast. The Godavari River basin area is second in size
only to the Ganga; its delta on the east coast is also one of the
country's main rice-growing areas. It is known as the "Ganga of the
South," but its discharge, despite the large catchment area, is
moderate because of the medium levels of annual rainfall, for example,
about 700 millimeters at Nasik and 1,000 millimeters at Nizamabad.
The Krishna rises in the Western Ghats and flows east into the Bay of
Bengal. It has a poor flow because of low levels of rainfall in its
catchment area--660 millimeters annually at Pune. Despite its low
discharge, the Krishna is the third longest river in India.
The source of the Kaveri is in the state of Karnataka, and the river
flows southeastward. The waters of the river have been a source of
irrigation since antiquity; in the early 1990s, an estimated 95 percent
of the Kaveri was diverted for agricultural use before emptying into the
Bay of Bengal. The delta of the Kaveri is so mature that the main river
has almost lost its link with the sea, as the Kollidam, the distributary
of the Kaveri, bears most of the flow.
The Narmada and the Tapti are the only major rivers that flow into
the Arabian Sea. The Narmada rises in Madhya Pradesh and crosses the
state, passing swiftly through a narrow valley between the Vindhya Range
and spurs of the Satpura Range. It flows into the Gulf of Khambhat (or
Cambay). The shorter Tapti follows a generally parallel course, between
eighty kilometers and 160 kilometers to the south of the Narmada,
flowing through the states of Maharashtra and Gujarat on its way into
the Gulf of Khambhat.
Harnessing the waters of the major rivers that flow from the
Himalayas is an issue of great concern in Nepal, India, and Bangladesh.
Issues of flood control, drought prevention, hydroelectric power
generation, job creation, and environmental quality--but also
traditional lifestyles and cultural continuities--are at stake as these
countries grapple with the political realities, both domestic and
international, of altering the flow of the Ganga and Brahmaputra.
Although India, Nepal, and Bangladesh seek to alleviate problems through
cooperation over Himalayan rivers, irrigation projects altering the flow
of Punjab-area rivers are likely to continue to be an irritant between
India and Pakistan--countries between which cooperation is less likely
to occur--in the second half of the 1990s. Internally, large dam
projects, such as one on the Narmada River, are also controversial (see
Development Programs, ch. 7).
India - Climate
The Himalayas isolate South Asia from the rest of Asia. South of
these mountains, the climate, like the terrain, is highly diverse, but
some geographers give it an overall, one-word characterization--violent.
What geographers have in mind is the abruptness of change and the
intensity of effect when change occurs--the onset of the monsoon rains,
sudden flooding, rapid erosion, extremes of temperature, tropical
storms, and unpredictable fluctuations in rainfall. Broadly speaking,
agriculture in India is constantly challenged by weather uncertainty.
It is possible to identify seasons, although these do not occur
uniformly throughout South Asia. The Indian Meteorological Service
divides the year into four seasons: the relatively dry, cool winter from
December through February; the dry, hot summer from March through May;
the southwest monsoon from June through September when the predominating
southwest maritime winds bring rains to most of the country; and the
northeast, or retreating, monsoon of October and November.
The southwest monsoon blows in from sea to land. The southwest
monsoon usually breaks on the west coast early in June and reaches most
of South Asia by the first week in July (see fig. 6). Because of the
critical importance of monsoon rainfall to agricultural production,
predictions of the monsoon's arrival date are eagerly watched by
government planners and agronomists who need to determine the optimal
dates for plantings.
Theories about why monsoons occur vary. Conventionally, scientists
have attributed monsoons to thermal changes in the Asian landmass.
Contemporary theory cites other factors--the barrier of the Himalayas
and the sun's northward tilt (which shifts the jet stream north). The
hot air that rises over South Asia during April and May creates
low-pressure areas into which the cooler, moisture-bearing winds from
the Indian Ocean flow.These circumstances set off a rush of
moisture-rich air from the southern seas over South Asia.
The southwest monsoon occurs in two branches. After breaking on the
southern part of the Peninsula in early June, the branch known as the
Arabian Sea monsoon reaches Bombay around June 10, and it has settled
over most of South Asia by late June, bringing cooler but more humid
weather. The other branch, known as the Bay of Bengal monsoon, moves
northward in the Bay of Bengal and spreads over most of Assam by the
first week of June. On encountering the barrier of the Great Himalayan
Range, it is deflected westward along the Indo-Gangetic Plain toward New
Delhi. Thereafter the two branches merge as a single current bringing
rains to the remaining parts of North India in July.
The withdrawal of the monsoon is a far more gradual process than its
onset. It usually withdraws from northwest India by the beginning of
October and from the remaining parts of the country by the end of
November. During this period, the northeast winds contribute to the
formation of the northeast monsoon over the southern half of the
Peninsula in October. It is also known as the retreating monsoon because
it follows in the wake of the southwest monsoon. The states of Tamil
Nadu, Karnataka, and Kerala receive most of their rainfall from the
northeast monsoon during November and December. However, 80 percent of
the country receives most of its rainfall from the southwest monsoon
from June to September.
South Asia is subject to a wide range of climates--from the
subfreezing Himalayan winters to the tropical climate of the Coromandel
Coast and from the damp, rainy climate in the states of Assam and West
Bengal to the arid Great Indian Desert. Based on precipitation and
temperature, experts define seven climatic regions: the Himalayas, Assam
and West Bengal, the Indo-Gangetic Plain, the Western Ghats and coast,
the Deccan (the interior of the Peninsula south of the Narmada River),
and the Eastern Ghats and coast (see fig. 7).
In the Himalayan region, climate varies with altitude. At about 2,000
meters, the average summer temperature is near 18�C; at 4,500 meters,
it is rarely above 0�C. In the valleys, summer temperatures reach
between 32�C and 38�C. The eastern Himalayas receive as much as 1,000
to 2,000 millimeters more precipitation than do the Western Himalayas,
and floods are common.
Assam and West Bengal are extremely wet and humid. The southeastern
part of the state of Meghalaya has the world's highest average annual
rainfall, some 10,900 millimeters.
The Indo-Gangetic Plain has a varied climatic pattern. Rainfall and
temperature ranges vary significantly between the eastern and western
extremes (see table 2, Appendix). In the Peninsula region, the Western
Ghats and the adjoining coast receive heavy rains during the southwest
monsoon. Rainfall in the peninsular interior averages about 650
millimeters a year, although there is considerable variation in
different localities and from year to year. The Eastern Ghats receive
less rainfall than the western coast. Rainfall there ranges between 900
and 1,300 millimeters annually.
The northern Deccan region, bounded by the Western Ghats, the Vindhya
Range and the Narmada River to the north, and the Eastern Ghats,
receives most of its annual rainfall during the summer monsoon season.
The southern Deccan area is in a "rain shadow" and receives
only fifty to 1,000 millimeters of rainfall a year. Temperature ranges
are wide--from some 15�C to 38�C--making this one of India's most
comfortable climatic areas.
Throughout most of non-Himalayan India, the heat can be oppressive
and sometimes, such as was experienced in 1994 and 1995, literally can
be a killer. Hot, relatively dry weather is the norm before the
southwest monsoons, which, along with heavy rains and high humidity,
bring cloud cover that lowers temperatures slightly. Temperatures reach
the upper 30s�C and can reach as high as 48�C during the day in the
premonsoon months.
India - Earthquakes
