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ICE Case Studies
Number 107, December 2005

Mohenjo-Daro, Aryan Invasions and Shifting Environments, by Jim Lee

I. Case Background
II. Environment Aspect
III. Conflict Aspect
IV. Env. - Conflict Overlap
V. Related Information


1. Abstract

From the city-states of Iraq, people spread in all directions, including the East. One group, that some call the Aryans, emerged on the steppes of Eurasia. They were mostly herders of animals and had little in the way of settled city areas. The Aryans replaced the earlier Dravidian cultures and imposed a new society. Extensive excavations at the key cities of Harappa and Mohenjo-daro suggest that Dravidian culture was fully in place by 2500 B.C.

2. Description

“Mohenjo-Daro was a city located on the south of Modern Pakistan in the Sind Province, in the right bank of the Indus River.” Meaning “mound of the dead”, it was one of the major cities of the Harappan civilization. While the city was abandoned around 1,700 bc, around the time of the Aryan invasions, it was thought that the underlying cause was a change in the course of the Indus River.

Was there some catastrophic event? Geologists suggest that earthquakes in southern Pakistan, through rock slides, effectively dammed the Indus River and prevented it from running down to the Indian Ocean. The Indus River would have broken its banks and flooded the surrounding plains, submerging many of the fields.” It may have also drowned the city and people of Mohenjo-Daro.

The Aryans peoples began moving westward from their home in steppes of Eurasia sometime around 4000 years ago. “In Sanskrit they were the “Aryas” (“Aryans”); but that root “ar”, would also serve as the foundation of the name of the conquered Persian territories, “Iran”. They first entered India in the Indus River valley and found huge forests. “Clearing the forests over the centuries was an epic project and one that is still preserved in Indian literature.”
Aryan peoples entered the Punjab about 1500 BC from the grasslands and steppes of central Asia and conquered the darker-skinned Dravidian peoples (and others). Their lifestyle was nomadic, based on raising cattle.

Over time, the Aryans drove further into the subcontinent and pushed the dark-skinned Dravidians, who preceded them, to the south. The Aryans were illiterate, pastoral, spoke an Indo-European language. They created the basis for India’s caste system that favored them over the Dravidians they conquered.

The understanding of migration into the Indian sub-continent has a long history and a long period of debate. “British, Germans, Europeans as a whole, and interestingly Indian intellectuals in British ruled India as well, believed that about 1500 BC a nomadic people, called Aryans, invaded northwest frontiers of India, coming from the Central Asia or some part of Europe through the passes like Khyber in Hindu Kush range and defeated and drove away the local inferior Dravidians.”

Mahenjo-Daro was a key Dravidian center and built with conflict in mind. “Defensively Mohenjo-daro was a well fortified city. Though it did not have city walls it did have towers to the west of the main settlement, and defensive fortifications to the south.” The city was built to be a military and commercial center. It was an outpost for a new civilization. The BJP Party of India disputes these historical theories and explanations. “Hence, our alternative explanation is that Barbarians came to India from outside and established Aryan civilization by coming in contact with Indian or Hindu Aryans.”

“With the ending of the Ice Age, around 10,000 years ago, Himalayan glaciers melted and flowed into the Saraswati. Due to earthquakes and great floods it changed its course over six times.” With the end of glacier melt and a drying climate the river began to dry up and it no longer flowed into the Arabian Sea. The many cities that developed along the river eventually expired. The only cities to develop outside of this region were Harappa and Mohenjo-daro.

The end of the Ice Age and the extraordinary period of global warming about 10,000 years ago produced social impacts in South Asia, as it had in other parts of the world. As in the Middle East, “the melting of ice from the snow capped peaks of the Himalayas began ten thousand years ago. The trickling flow of clean and pure water merged into streams and currents and turned into confluence of streams that turned into rivers flowing down the slopes into the plains of northwest India. The fertile area came to be other “edens” that emerged with early urban settlement patterns along the banks of lush and fertile rivers. This is especially true in South Asia where the Saraswati, Indus, Yamuna, Ravi, Beas, Sutlej, and Ganges are a few rivers that can be named as having formed out of this melting of ice caps.” (This was also the case in the Middle East.) As the ice receded, humans advanced.

From 8,000 BC, the Mesolithic age began and spread into the Indian sub-continent around 4,000 BC. During this time, hunters used sharp and pointed tools for hunting and killing fast-moving animals. The beginning of plant cultivation appeared. The Chotanagpur Plateau, central India and south of the river Krishna are various Mesolithic sites on the sub-continent. Neolithic (New Stone Age) settlements date back to 4,000 BC. These cultures evolved into the Indus Valley or Harappan civilization. These were the Dravidians.

Urban settlements began in South Asia as they had in the Middle East, originating in river valleys. There was considerable technology transfer over a long period of time that included ideas of social organization. “Sometime around 6000 BCE a nomadic herding people settled into villages in the mountainous region just west of the Indus River. There they grew barley and wheat using sickles with flint blades, and they lived in small houses built with adobe bricks. After 5000 BCE [Before the Common Era], the climate in their region changed, bringing more rainfall, and apparently, they were able to grow more food, for they grew in population. They began domesticating sheep, goats and cows and then water buffalo. After 4000 BCE they began to trade beads and shells with distant areas in central Asia and areas west of the Khyber Pass and they began using bronze and working metals.”

Why Mohenjo-daro rose and fell is still a matter of debate. It may have been a victim of its own success. “Another theory suggests that the decline was led by population boom. Houses became increasingly overcrowded; increasingly, buildings and even courtyards were sub-divided. Space available for occupation diminished due to the steadily rising levels of the Indus.”
The Bharatiya Janata Part became the opposition leader in India in 1991 and “took power in four key Indian states. The BJP-led opposition ordered the rewriting of history textbooks so that they refer to a glorious Hindi past and denigrate Muslim kings.”

3. Duration: 2500-1700 BC

4. Location

Continent: Asia
Region: South Asia
Country: India

5. Actors: Dravidians, Aryans

II. Environment Aspects

6. Type of Environmental Problem: Habitat Change

A wet period of climate followed and produced a myriad of environmental impacts. “The climate changed again, bringing still more rainfall, and on the nearby plains, through which ran the Indus River, grew jungles inhabited by crocodiles, rhinoceros, tigers, buffalo and elephants. By around 2600 B.C., a civilization as sophisticated as Mesopotamia and Egypt had begun on the Indus Plain and surrounding areas...Along the Indus and other major rivers in South Asia, there were seventy or more cities. The composition or peoples of cities varied with specialty. There were cities from the foothills of the Himalayan Mountains to Malwan in the south. There was the city of Alamgirpur in the east and Sutkagen Dor by the Arabian Sea in the west.”

The arrival of cities coincided with the arrival of new building techniques and the creation of houses (that replaced tents which had replaced caves). The invention of building technologies allowed humans to create their own personalized caves at locations nearby to food sources. “One of these cities was Mohenjo-Daro, on the Indus River some 250 miles north of the Arabian Sea, and another city was Harappa, 350 miles to the north on a tributary river, the Ravi. Each of these two cities had populations as high as around 40,000.” The infrastructure of the city relied on the use of the newest building technology – bricks. Most buildings in these early cities were constructed with manufactured, standardized, baked bricks. Over the centuries, the need for wood for brick making (for making a fire to bake the bricks) denuded the countryside and may have contributed to the downfall of the cities (through resource and declining energy supply). The discovery of kilns to make bricks was thought to be used extensively in domestic and public buildings. The Harappans used the same size bricks and standard weights as the people of Mohenjo-Daro, indicating some degree of technology transfer and standardization.”

The technology of agricultural production that began along the Tigris-Euphrates spread more rapidly to the east than the west. South Asian, Southeast Asian and East Asian cities arose and adopted similar subsistence production systems based on large, fertile river valleys that enjoyed seasonal fluctuations of flooding. This spread was slower in the east. Specialization led to surpluses and trade and thus the development of external relations. “Wheat, barley and the date palm were cultivated; animals were domesticated; and the cotton textiles, ivory and copper were exported to Mesopotamia, and possibly China and Burma in exchange for silver and other commodities. Production of several metals such as copper, bronze, lead and tin also began and some remnants of furnaces provide evidence of this fact.

The early Rigvedic period last from roughly 1700 to 1000 b.c. and spawned the earliest literature in the region the Rig Veda poems. This period also initiated the caste systems. These Aryans started with only two classes, noble and common. After conquering the darker skinned Dravidians they “added a third: the Dasas, or “darks” and a fourth for the priests of the new religion. In the Later Vedic Period that lasted from 1000 to 500 b.c., the Aryans cut through the forests and reached the Ganges River. During this time the great epics, the Mahabharata and the Ramayana, were written.

The Indus Valley civilization lasted from about 2500 b.c. to 1700 b.c. and the invasion of the Aryans. “It is possible that the periodic shifts in the courses of the major rivers of the valley may have deprived the cities of flood waters necessary for their surrounding agricultural lands.” The food shortage led to structural weakness and vulnerability to Aryans raiders.
Between the years 1800 and 1700 BCE, the Dravidian city of Mohenjo-Daro on the Indus Plain vanished, for reasons still unclear. One cause may have been a shift in the Indus River, which deprived the city of its water source and made it more vulnerable to attack in order to secure supplies. This geographic shift, along with the arrival of the Aryans, led to an unforeseen environmental calamity.

“People dammed the water along the lower portion of the Indus River without realizing the consequences: temporary but ruinous flooding up river, flooding that would explain the thick layers of silt thirty feet above the level of the river at the site of Mohenjo-Daro. Another suspected cause is a decline in rainfall and an accompanying drop off in the abundance of food. This could also indicate an insufficient military strength and will to secure food supplies from distant areas. Whatever the causes, people abandoned the city in search of food. Later, a few people of a different culture settled in some of the abandoned cities such as Mohenjo-Daro, in what archaeologists call a "squatter period." Then the squatters disappeared. Knowledge of the Mohenjo-Daro civilization died -- until archaeologists discovered the civilization in the twentieth century.”

Rainfall declined in the Indus region between 1800 and 1700 BCE, but around 1500 BCE it increased again, making the Indus Plain more fertile and productive. Between 1500 and 1200 BCE an illiterate, pastoral people -- the Aryans -- migrated from the steppe lands of central Russia through what is now Afghanistan, through the Khyber Pass and onto the (then) sparsely populated Indus Plain.

The changing environmental periods produced substantial impacts on the society. “Nearing the end of the Indus Valley Civilization, the cities began to wither and the strong economy slowly deteriorated. Most likely the intermittent floods put an end to this civilization. Floods wiped out the irrigation system that supplied water to the crops, and many of the buildings were smothered.”

7. Type of Habitat: Dry (Now)

8. Act and Harm Sites: Himalayas and Downstream Rivers

III. Conflict Aspects

9. Type of Conflict: Inter-state

The domestication of the horse in Eurasia provided a critical step in both political and technological development in South Asia. Originating in the steppes of Asia, the horse with a stirrup provided a considerable economic and military advantage. Some scholars believe that the horse was the key to the Mongol’s ability to create the largest empire in human history around the 13th century. Much of the later military domination of the New World by the Old World is attributable to the differential natural endowments of the Middle Eastern and American eco-systems. This is especially true in the case of the horse. The extinction of potential animal domesticates among the Pleistocene mega fauna rendered the American Indians vulnerable to military conquest by European adventurers mounted on horseback.

Drawing from rather mundane inventions such as the stirrup and the animal-driven plow, the chariot was the next great military invention. One factor in the fall of Mohenjo-Daro was the vast migrations of chariot peoples in the 2nd millennium B.C. These people’s possessed superior military resources and technology compared to the Dravidians. During King Solomon's reign over Israel (970-931 B.C.), chariots and horses were imported from Egypt and exported to Asia Minor.

10. Level of Conflict: Low

11. Fatality Level of Dispute: 10,000 (speculative estimate)

IV. Environment and Conflict Overlap

12. Environment-Conflict Link and Dynamics: Indirect

Causal Diagram

13. Level of Strategic Interest: Regional

14. Outcome of Dispute: Loss

“The BJP contends Aryans were the original inhabitants of the entire country and they were the founders of the two main Hindu cultures, Vedic and Harappian.” Archaeological finds suggest that Aryans were related only to the Vedic culture. The BJP perspective intends to provide a unified history of all Indians, both north and south (generally Aryans versus Dravidian peoples). This is currently aimed at identifying Indian Muslim as foreigners and latter day invaders. This view would be diluted if their origins were from Aryans, who themselves were foreigners.

V. Related Information and Sources

15. Related ICE Cases

16. Relevant Websites and Literature

“Ancient India: The Aryans”,`dee/ANCINDIA/ARYANS.HTM, accessed 8/6/2004.

”Mohenjo-Daro”,, accessed August 5, 2004.

History & Culture, Moen-Jo-Daro

“Ancient India: The Aryans”, accessed 8/6/2004.

Dr. CS Shah August 5, 2001, “Indo-Aryans and Their History”, Copyright, Accessed Dec. 29, 2001.

“Antiquity”, Chapter 6, India, Hinduism, and Religious Rebellion, to 480 BCE: The Lost Civilization of Mohenjo-Daro.

HARP - Harappa Archaeological Research Project.

BJP Today, June 1-15, 2003 - Vol. 12, No. 11, Basudeb Ghose, “Redisovering Vedic Era”,, accessed August 5, 2004.