Indus valley civilization, ancient civilization that flourished from about 2500 B.C. to about 1500 B.C. in the valley of the Indus River and its tributaries, in the northwestern portion of the Indian subcontinent, i.e., present-day Pakistan. At its height, its geographical reach exceeded that of Egypt or Mesopotamia. Since 1921 this civilization has been revealed by spectacular finds at Mohenjo-Daro, an archaeological site in NW Sind, and at Harappa, in central Punjab near the Ravi River. These sites, each of which measures more than 3 mi (5 km) in circumference, were once great urban centers, the chief cities of the Indus civilization. They had large and complex hill citadels, housing palaces, granaries, and baths that were probably used for sacred ablutions; the great bath at Mohenjo-Daro was c.40 ft (12 m) long and 23 ft (7 m) wide. Beyond the citadels were well-planned towns, laid out in rectangular patterns. Houses, often two-storied and spacious, lined the town streets; they had drainage systems that led into brick-lined sewers. The economy of the Indus civilization was based on a highly organized agriculture, supplemented by an active commerce, probably connected to that of the ancient civilizations of Mesopotamia. The arts flourished there, and many objects of copper, bronze, and pottery, including a large collection of terra-cotta toys, have been uncovered. Most notable, however, are the steatite seals, exquisitely engraved with animal figures and often bearing a line of pictographic script. On some seals are depicted a bo tree or, as some authorities hold, a Babylonian tree of life, and others have as their central figure the god Shiva, who later became preeminent in the Hindu pantheon. The writing, long a riddle to archaeologists, has yet to be satisfactorily deciphered; the language appears to be structurally related to the Dravidian languages. The origin, rise, and decline of the Indus valley civilization remain a mystery, but it seems most probable that the civilization fell (c.1500 B.C.) to invading Aryans.

Indus, chief river of Pakistan, c.1,900 mi (3,060 km) long, rising in the Kailas range in the Tibetan Himalayas, and flowing W across Jammu and Kashmir, India, then SW through Pakistan to the Arabian Sea SE of Karachi. The upper Indus, fed by snow and glacial meltwater from the Karakorum, Hindu Kush, and Himalayan mts., flows through deep gorges and scenic valleys. The turbulence of its rushing waters makes it unsuitable for navigation.

The Indus then flows onto the dry Punjab plains of Pakistan and becomes a broad, slow-moving, silt-laden stream. There it receives the combined waters of the five rivers of the Punjab (Chenab, Jhelum, Ravi, Beas, and Sutlej), its chief affluent. In Pakistan the Indus is extensively used for irrigation and hydroelectric-power generation. The Jinnah, Sukker, and Kotri barrages feed the main Indus canals in W Punjab and Sind. The irrigated plain is Pakistan's most densely populated region and its main agricultural area; wheat, corn, rice, millet, dates, and fruits are the chief crops.

The lower Indus is navigable for small boats but is little used for transportation, at least since the development of railroads. The extensive use of the Indus's waters for irrigation has greatly reduced the flow of freshwater in the lower Indus, leading to the encroachment of saltwater up the lower river and the loss to the Sind of millions of acres of surrounding farmland to the sea or salt and of hundreds of thousands of acres of ecologically important mangrove swamp.

The river valley was the site of the prehistoric Indus valley civilization, and the Indus was once considered to be the western boundary of India. The use of the Indus and its tributaries has been a source of conflict between Pakistan and India, although a treaty by which the waters were to be shared was signed in 1960; the use of the river system's waters also is an issue between the provinces of Punjab and Sind within Pakistan.

(circa 2500–circa 1700 BC) Earliest known urban culture of the Indian subcontinent and the most extensive of the world's three earliest civilizations. It stretched from near the present-day Iran-Pakistan border on the Arabian Sea in the west to near Delhi in the east, and 500 mi (800 km) to the south and 1,000 mi (1,600 km) to the northeast. It is known to have included two large cities, Harappa and Mohenjo Daro (in what is now Pakistan), whose large size suggests centralization in two large states or one state with two capitals. Alternatively, Harappa may have succeeded Mohenjo Daro. It was a literate civilization; the language has been tentatively identified as Dravidian. Wheat and barley were grown, many animals (including cats, dogs, and cattle) were domesticated, and cotton was cultivated. The best-known artifacts are seals depicting real and imaginary animals. How and when the civilization came to an end is unclear; Mohenjo Daro was attacked and destroyed in the mid-2nd millennium BC, but in the south there was continuity between the Indus civilization and the Copper Age civilizations of central and western India.

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