The Indus Valley Civilization

What We've Learned about the Indus Valley in the Last Century

Stone engraving from the Indus Valley of a person sitting surrounded by animals
Stone seal from the Indus Valley, which can be viewed at the National Museum of New Delhi, dated to between 2500 and 2400 B.C.E.

Angelo Hornak / Getty Images

When 19th-century explorers and 20th-century archaeologists rediscovered the ancient Indus Valley civilization, the history of the Indian sub-continent had to be rewritten.* Many questions remain unanswered.

The Indus Valley civilization is an ancient one, on the same order as Mesopotamia, Egypt, or China. All these areas relied on important rivers: Egypt relying on the annual flooding of the Nile, China on the Yellow River, the ancient Indus Valley civilization (aka Harappan, Indus-Sarasvati, or Sarasvati) on the Sarasvati and Indus rivers, and Mesopotamia outlined by the Tigris and Euphrates rivers.

Like the people of Mesopotamia, Egypt, and China, the people of the Indus civilization were culturally rich and share a claim to the earliest writing. However, there is a problem with the Indus Valley that doesn't exist in such pronounced form elsewhere.

Evidence is missing elsewhere, through the accidental depredations of time and catastrophes or deliberate suppression by human authorities, but to my knowledge, the Indus Valley is unique among major ancient civilizations in having a major river disappear. In place of the Sarasvati is the much smaller Ghaggar stream that ends in the Thar desert. The great Sarasvati once flowed into the Arabian Sea, until it dried up in about 1900 B.C. when the Yamuna changed course and instead flowed into the Ganges. This may correspond with the late period of the Indus Valley civilizations.

  • Mohenjo-Daro - From Archaeology at

The mid-second millennium is when the Aryans (Indo-Iranians) may have invaded and possibly conquered the Harappans, according to a very controversial theory. Before then, the great Bronze Age Indus Valley civilization flourished in an area greater than one million square km. It covered "parts of Punjab, Haryana, Sindh, Baluchistan, Gujarat, and fringes of Uttar Pradesh"+. On the basis of artifacts of trade, it appears to have flourished at the same time as the Akkadian civilization in Mesopotamia.

Indus Housing

If you look at an Harappan housing plan, you'll see straight lines (a sign of deliberate planning), orientation to the cardinal points, and a sewer system. It held the first great urban settlements on the Indian subcontinent, most notably at the citadel cities of Mohenjo-Daro and Harappa.

Indus Economy and Subsistence

The people of the Indus Valley farmed, herded, hunted, gathered, and fished. They raised cotton and cattle (and to a lesser extent, water buffalo, sheep, goats, and pigs), barley, wheat, chickpeas, mustard, sesame, and other plants. They had gold, copper, silver, chert, steatite, lapis lazuli, chalcedony, shells, and timber for trading.


The Indus Valley civilization was literate -- we know this from seals inscribed with a script that is now only in the process of being deciphered. [An aside: When it is finally deciphered, it should be a big deal, as was Sir Arthur Evans' deciphering of Linear B. Linear A still needs deciphering, like the ancient Indus Valley script.] The first literature of the Indian subcontinent came after the Harappan period and is known as Vedic. It doesn't appear to mention the Harappan civilization.

The Indus Valley civilization flourished in the third millennium B.C. and suddenly disappeared, after a millennium, in about 1500 B.C. -- possibly as a result of tectonic/volcanic activity leading to the formation of a city-swallowing lake.

Next: Problems of the Aryan Theory in Explaining Indus Valley History

*Possehl says that prior to the archaeological investigations starting in 1924, the earliest reliable date for the history of India was spring of 326 B.C. when Alexander the Great raided the northwestern border.


  1. "Imaging River Sarasvati: A Defence of Commonsense," by Irfan Habib. Social Scientist, Vol. 29, No. 1/2 (Jan. - Feb., 2001), pp. 46-74.
  2. "Indus Civilization," by Gregory L. Possehl. The Oxford Companion to Archaeology. Brian M. Fagan, ed., Oxford University Press 1996.
  3. "Revolution in the Urban Revolution: The Emergence of Indus Urbanization," by Gregory L. Possehl. Annual Review of Anthropology, Vol. 19, (1990), pp. 261-282.
  4. "The Role of India in the Diffusion of Early Cultures," by William Kirk. The Geographical Journal, Vol. 141, No. 1 (Mar., 1975), pp. 19-34.
  5. +"Social Stratification in Ancient India: Some Reflections," by Vivekanand Jha. Social Scientist, Vol. 19, No. 3/4 (Mar. - Apr., 1991), pp. 19-40.

A 1998 article, by Padma Manian, on world history textbooks gives an idea of what we may have learned about the Indus Civilization in traditional courses, and debated areas:

"Harappans and Aryans: Old and New Perspectives of Ancient Indian History," by Padma Manian. The History Teacher, Vol. 32, No. 1 (Nov., 1998), pp. 17-32.

Major Cities

  • All the textbooks Manian examines mention the cities of Harappa and Mohenjo Daro, their urban features of ordered streets, sewers, citadels, granaries and the bath at Mohenjo-Daro, artifacts, including seals in a yet undeciphered language. Some authors mention the area of civilization was more than a million square kilometers. One author mentions another excavated city, Kalinagan, and most of the books mention the surrounding villages.


  • Most date the Indus Valley civilization from 2500-1500 B.C., although there is an alternative, 3000-2000. The year 1500 is listed as the year of the Aryan (or Indo-Iranian) invasion.

Decline of the Indus Civilization

  • Some attribute the fall of the Indus civilization to the Aryans, destroyers and enslavers of the Indus people. Others say environmental changes caused the fall. Some say both.

Identification of the Aryans

  • The books call the Aryans pastoral nomads. Their origins include grasslands of Eastern Europe/Western Asia, the Caspian Sea, Anatolia, and south-central Asia. The books also claim they came with cattle and some say they already had iron weapons, while others say they developed them in India. One claims they crossed the Himalayas in horse-drawn chariots.

Victory Over the Indigenous People

  • All the textbooks assume the Aryans were victorious and regard the Vedas as written by these invaders.


  • There are various interpretations of the caste system. In one, when the Aryans arrived on the scene there were already 3 castes in India. In another interpretation, the Aryans brought and imposed their own tripartite system. The dark-skinned people are generally considered the conquered people and the lighter-skinned ones, the Aryans.

Problems With the Aryan Theory in the Typical Presentations


  • The idea that Harappan civilization fell as a result of the arrival of the Aryans. Harappa had lost its urban character by 2000 B.C., 500 years before the Aryan arrival.

Traces of Harappa Elsewhere

  • Indicators of refugees, including lustrous Red Ware, until about 1000 B.C. Refugees fled north-eastward; some residents east to the Gulf of Cambay.

Lack of Aryan Traces

  • Painted Grey Ware pottery formerly attributed to the Aryans has not been found along their possible courses, but appears to be an outgrowth of earlier Indian styles.


  • Historical linguistic reasoning about the origin of the Aryans is faulty. (This is a complicated topic summarized by Kris Hirst.)

Nomad Status Questionable

  • Archaeologist Colin Renfrew denies that there is any evidence in the Rig Veda that Aryans were invaders or nomads.

Sarasvati Chronology

  • Since the Rig Vedas refer to the Sarasvati as a large river, they must have been written before 1900 B.C., so the people mentioned in it must have already been there.
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Gill, N.S. "The Indus Valley Civilization." ThoughtCo, Sep. 20, 2021, Gill, N.S. (2021, September 20). The Indus Valley Civilization. Retrieved from Gill, N.S. "The Indus Valley Civilization." ThoughtCo. (accessed May 30, 2023).