The Indus Valley Civilization, also called the Indus Civilization, was an ancient society in the northwestern part of South Asia. It existed from about 3300 BCE to 1300 BCE, with its most developed stage from 2600 BCE to 1900 BCE. Along with ancient Egypt and Mesopotamia, it was one of the three major early civilizations of the Near East and South Asia. Of these three, the Indus Civilization covered the largest area, including much of modern-day Pakistan, parts of northwestern India, and northeast Afghanistan. It thrived in the fertile plains of the Indus River, which flows through Pakistan, and near a system of rivers that once ran near the Ghaggar-Hakra, a seasonal river in northwest India and eastern Pakistan.
The term "Harappan" is also used to describe the Indus Civilization, named after Harappa, the first site of this culture to be studied in the early 20th century. Harappa was located in what was then the Punjab province of British India and is now part of Punjab, Pakistan. The discovery of Harappa and later Mohenjo-daro followed research that began in 1861 with the creation of the Archaeological Survey of India. Earlier and later stages of the culture, called Early Harappan and Late Harappan, existed in the same region. The Early Harappan culture developed from Neolithic societies, the most well-known of which is named after Mehrgarh in Balochistan, Pakistan. The Harappan Civilization is sometimes called Mature Harappan to differentiate it from earlier stages.
The cities of the Indus Civilization were known for their organized planning, homes made of baked bricks, advanced drainage and water systems, groups of large buildings that were not homes, and skilled crafts and metalwork. Harappa and Mohenjo-daro likely had between 30,000 and 60,000 people each, and the entire civilization may have had between 1 million and 5 million people at its peak. A gradual drying of the region during the 3rd millennium BCE may have encouraged the growth of cities. Over time, the reduced water supply likely contributed to the decline of the civilization and the movement of its people eastward.
More than 1,000 Mature Harappan sites have been identified, with nearly 100 studied in detail. The five largest cities include Mohenjo-daro (a UNESCO World Heritage Site in Pakistan), Harappa (in western Punjab), Ganeriwala (in the Cholistan Desert), Dholavira (a UNESCO World Heritage Site in western Gujarat, India), and Rakhigarhi (in Haryana, India). The language of the Harappan people is unknown because the writing system used by the Indus Civilization has not been fully understood. Some scholars suggest it may be related to the Dravidian or Elamo-Dravidian language families.
Etymology
The Indus Valley Civilization is named after the Indus River system. Early sites of this civilization were found and studied in the fertile areas near the river.
In archaeology, it is sometimes called the Harappan Civilization, named after Harappa, the first site discovered in the 1920s. This name is often used by the Archaeological Survey of India since the country gained independence in 1947.
The term "Ghaggar-Hakra" is now commonly used to describe the Indus Civilization because many sites were found along the Ghaggar-Hakra River in northwest India and eastern Pakistan. Other names, such as "Indus-Sarasvati Civilization" and "Sindhu-Saraswati Civilization," have been used by some scholars. These names connect the Ghaggar-Hakra River to the Sarasvati River mentioned in the Rigveda, an ancient Sanskrit text from around the second millennium BCE. These names are not directly related to the later stages of the Indus Valley Civilization.
Recent scientific studies suggest that the Ghaggar-Hakra River was once a system of rivers fed by monsoons, not snowmelt as described in the Rigveda. These rivers became seasonal, or dry during certain times of the year, around the time the civilization declined, about 4,000 years ago.
Extent
The Indus Valley Civilization existed around the same time as other ancient river-based civilizations, such as Ancient Egypt along the Nile, Mesopotamia near the Euphrates and Tigris rivers, and China in the Yellow River and Yangtze River regions. During its mature stage, the Indus Valley Civilization covered a larger area than these other civilizations. It included a central region extending about 1,500 kilometers (900 miles) along the floodplain of the Indus River and its tributaries. Additionally, a much larger area—up to ten times the size of the central region—was influenced by the Indus Valley Civilization’s culture and economy.
Agriculture began in Balochistan, near the edges of the Indus floodplain, around 6500 BCE. Over the next few thousand years, settled life spread across the Indus plains, leading to the development of villages and cities. This organized way of life increased the birth rate. Major cities like Mohenjo-daro and Harappa likely had populations of 30,000 to 60,000 people. During the civilization’s peak, the population of the Indian subcontinent may have reached 4 to 6 million. However, crowded living conditions and close contact with domestic animals increased the spread of diseases, which raised the death rate. Some estimates suggest the Indus Valley Civilization’s population at its height was between 1 and 5 million.
At its height, the civilization stretched from Balochistan in the west to western Uttar Pradesh in the east, from northeastern Afghanistan in the north to Gujarat in the south. The most sites were found in the Punjab region, Gujarat, Haryana, Rajasthan, Uttar Pradesh, Jammu and Kashmir, Sindh, and Balochistan. Coastal settlements ranged from Sutkagan Dor in western Balochistan to Lothal in Gujarat. The farthest northern site was Shortugai on the Oxus River in Afghanistan, while the farthest southern site was Daimabad in Maharashtra. Indus Valley sites were often located along rivers, but some were also found on ancient coastlines, such as Balakot, and on islands, like Dholavira.
Discovery and history of excavation
Three other scholars whose names I cannot ignore are the late Mr. R. D. Banerji, who discovered the great age of Mohenjo-daro, and his successors, Messrs. M. S. Vats and K. N. Dikshit. No one, except myself, probably understands the challenges they faced during the first three years of work at Mohenjo-daro.
The first modern descriptions of the ruins of the Indus civilization were made by Charles Masson, who left the army of the East India Company. In 1829, Masson traveled through the Punjab region, giving the Company information in exchange for protection. He was also required to give the Company any historical items he found during his journey. Masson studied ancient texts, especially those about Alexander the Great’s battles, and visited places connected to those battles. His most important discovery in the Punjab was Harappa, a large city of the Indus civilization near the Ravi River. Masson recorded and drew many artifacts found at Harappa, many of which were partly buried. In 1842, he wrote about Harappa in a book called Narrative of Various Journeys in Baluchistan, Afghanistan, and the Punjab. He incorrectly believed Harappa was from the time of Alexander the Great’s campaign. Masson noted the site’s large size and the mounds of dirt formed by erosion over time.
Two years later, the East India Company sent Alexander Burnes to travel up the Indus River to study water travel for the army. Burnes visited Harappa and observed the baked bricks used in ancient buildings but also saw that local people had taken bricks from the site.
Despite these reports, Harappa was damaged more severely after the British took control of the Punjab in 1848–49. Many bricks were taken from the site to build railway tracks in the Punjab. By the mid-1850s, about 160 kilometers (100 miles) of railway track between Multan and Lahore used bricks from Harappa.
In 1861, three years after the East India Company was dissolved and Britain took direct control of India, the Archaeological Survey of India (ASI) was created to organize archaeological work. Alexander Cunningham, the ASI’s first leader, visited Harappa in 1853 and saw the large brick walls there. He returned later to study the site, which had been disturbed by people taking bricks. Although he wanted to prove Harappa was a lost Buddhist city mentioned by a Chinese traveler named Xuanzang, he could not find evidence of this. Instead, he published findings in 1875, including a Harappan seal with a script he believed came from outside India.
Archaeological work at Harappa slowed until 1904, when Lord Curzon, a British leader in India, passed a law to protect ancient sites and appointed John Marshall to lead the ASI. Marshall later assigned Hiranand Sastri to study Harappa, who concluded the site was older than a Buddhist city. Marshall then ordered ASI archaeologist Daya Ram Sahni to dig at the site’s two mounds.
Further south, in the Indus Valley of Sindh province, the largely untouched site of Mohenjo-daro had drawn attention. Marshall sent several ASI officers to study the site, including D. R. Bhandarkar (1911), R. D. Banerji (1919, 1922–1923), and M. S. Vats (1924). In 1923, Banerji wrote to Marshall, suggesting Mohenjo-daro was very old and noting similarities between its artifacts and those found at Harappa. Later that year, Vats also wrote to Marshall, noting similar seals and scripts at both sites. Based on these findings, Marshall ordered data from both sites to be compared and invited Banerji and Sahni to discuss the discoveries. By 1924, Marshall believed the finds were important and wrote in the Illustrated London News:
"Rarely have archaeologists had the chance to discover the remains of a forgotten civilization, as Schliemann did at Tiryns and Mycenae or Stein did in Turkestan. It seems now that we may be on the verge of such a discovery in the Indus plains."
A week later, British scholar Archibald Sayce noted that similar seals found in Mesopotamia and Iran were from the Bronze Age, giving the first strong clue about their age. Systematic excavations at Mohenjo-daro began in 1924–25 with K. N. Dikshit, followed by H. Hargreaves (1925–1926) and Ernest J. H. Mackay (1927–1931). By 1931, much of Mohenjo-daro had been explored, though some work continued, including a 1944 excavation led by Mortimer Wheeler, a new ASI leader, and Ahmad Hasan Dani.
After India was divided in 1947, most Indus Valley sites in Pakistan were studied by the Archaeological Survey of India, which focused on the Ghaggar-Hakra river system in India. Some believed this system might have more sites than the Indus Valley. According to archaeologist Shireen Ratnagar, many Ghaggar-Hakra sites in India are from local cultures with connections to the Harappan civilization but are not fully developed Harappan sites. By 1977, about 90% of Indus script seals and objects were found in Pakistan, with the rest in India. By 2002, over 1,000 Mature Harappan cities and settlements had been reported, with about 100 excavated, mainly near the Indus and Ghaggar-Hakra rivers. Only five major cities—Harappa, Mohenjo-daro, Dholavira, Ganeriwala, and Rakhigarhi—were identified. By 2008, 616 sites had been reported in India and 406 in Pakistan.
In India, the ASI focused on linking archaeology to national unity after 1947, while in Pakistan, efforts centered on Islamic heritage. After the partition, Mortimer Wheeler helped establish archaeological institutions in Pakistan and worked with UNESCO to preserve Mohenjo-daro. Other international projects included the German Aachen Research Project Mohenjo-daro, the Italian Mission to Mohenjo-daro, and the US Harappa Archaeological Research Project (HARP) started by George F. Dales. A flood later exposed part of an archaeological site near the area.
Chronology
The cities of the ancient Indus had social hierarchies, a writing system, well-planned cities, and long-distance trade. These features help archaeologists recognize them as a complete civilization. The main period of the Harappan civilization lasted from about 2600 to 1900 BCE. When including earlier and later cultures—Early Harappan and Late Harappan—the entire Indus Valley Civilization may have existed from the 33rd to the 14th centuries BCE. This civilization is part of the Indus Valley Tradition, which also includes the pre-Harappan occupation of Mehrgarh, the earliest farming site in the Indus Valley.
Archaeologists use different ways to divide the history of the Indus Valley Civilization. The most common method separates it into Early, Mature, and Late Harappan phases. Another method, proposed by Shaffer, divides the broader Indus Valley Tradition into four eras: the pre-Harappan "Early Food Producing Era," and the Regionalisation, Integration, and Localisation eras. These roughly match the Early Harappan, Mature Harappan, and Late Harappan phases.
Pre-Harappan era: Mehrgarh
Mehrgarh is a Neolithic (7000 BCE to about 2500 BCE) mountain site in the Balochistan province of Pakistan. It provided new information about the beginning of the Indus Valley Civilization. Mehrgarh is one of the earliest places in South Asia with evidence of farming and raising animals. It was influenced by the Neolithic culture of the Near East, with similarities in domesticated wheat, early farming, pottery, archaeological items, and domesticated plants and animals.
Jean-Francois Jarrige argues that Mehrgarh developed independently. He mentions the idea that farming was fully introduced from the Near East to South Asia, and he notes similarities between Neolithic sites in eastern Mesopotamia and the western Indus Valley, which show a "cultural continuum" between those areas. However, Jarrige concludes that Mehrgarh has an earlier local background and is not a "backwater" of the Near East's Neolithic culture.
Lukacs and Hemphill suggest that Mehrgarh began with local development, with cultural continuity but a change in population. They state that there is strong continuity between the Neolithic and Chalcolithic (Copper Age) cultures of Mehrgarh, but dental evidence shows the Chalcolithic population did not come from the Neolithic population, which suggests moderate levels of gene flow. Mascarenhas et al. (2015) note that new, possibly West Asian, body types appear in Mehrgarh graves starting in the Togau phase (3800 BCE).
Gallego Romero et al. (2011) state that their research on lactose tolerance in India suggests the west Eurasian genetic contribution identified by Reich et al. (2009) mainly reflects gene flow from Iran and the Middle East. They also note that the earliest evidence of cattle herding in South Asia comes from the Indus River Valley site of Mehrgarh and is dated to 7,000 years before present.
Early Harappan
The Early Harappan Ravi Phase, named after the nearby Ravi River, lasted from about 3300 BCE to 2800 BCE. It began when farmers from the mountains gradually moved between their mountain homes and the lowland river valleys. This phase is connected to the Hakra Phase, found in the Ghaggar-Hakra River Valley to the west, and came before the Kot Diji Phase (2800–2600 BCE, Harappan 2), named after a site in northern Sindh, Pakistan, near Mohenjo-daro. The earliest examples of the Indus script appeared around 3000 BCE.
The mature phase of earlier village cultures is shown by Rehman Dheri and Amri in Pakistan. Kot Diji represents the period leading up to the Mature Harappan era, with the citadel showing a form of leadership and a more urban lifestyle. Another town from this stage was found at Kalibangan in India on the Hakra River.
Trade networks connected this culture to other regional cultures and distant sources of raw materials, including lapis lazuli and other materials used for making beads. By this time, villagers grew many crops, such as peas, sesame seeds, dates, and cotton, and raised animals like water buffalo. Early Harappan communities moved to large urban centers by 2600 BCE, from where the mature Harappan phase began. Recent research shows that people from the Indus Valley moved from villages to cities.
The final stages of the Early Harappan period are marked by the building of large walled settlements, the expansion of trade networks, and the growing unity of regional communities into a "relatively uniform" material culture, including similar types of pottery, jewelry, and seals with Indus script, leading to the transition to the Mature Harappan phase.
Mature Harappan
According to Giosan et al. (2012), the slow movement of monsoons across Asia helped the Indus Valley villages grow by controlling the floods of the Indus River and its smaller rivers. Farming that relied on floodwaters created large food supplies, which supported the growth of cities. The people of the Indus Valley did not build irrigation systems. Instead, they depended on seasonal monsoons that caused summer floods. Brooke also notes that as rainfall decreased, cities became larger, which may have led to changes in how people lived and organized themselves.
According to J.G. Shaffer and D.A. Lichtenstein, the Mature Harappan civilization was a mix of cultural traditions, including the Bagor, Hakra, and Kot Diji groups, located in the Ghaggar-Hakra valley near the borders of India and Pakistan.
Maisels (2003) explains that the Harappan civilization began when different cultural groups, such as the Kot Diji and Amri-Nal, combined to form the Early Harappan period. He says that Mohenjo-daro and the Hakra-Ghaggar area were important early centers. In these places, Hakra-style pottery appeared before Kot Diji-style items. Maisels believes these areas helped bring together different cultural elements to create the Early Harappan civilization.
By 2600 BCE, Early Harappan communities became large cities. These cities included Harappa, Ganeriwala, and Mohenjo-daro in modern-day Pakistan, and Dholavira, Kalibangan, Rakhigarhi, Rupar, and Lothal in modern-day India. More than 1,000 settlements have been found, mostly near the Indus and Ghaggar-Hakra Rivers and their smaller rivers.
The Indus Valley Civilization had advanced cities that were among the first in the region. These cities showed careful planning, suggesting organized local governments that could plan and carry out large projects. These governments also valued public health and access to religious practices.
In cities like Harappa, Mohenjo-daro, and Rakhigarhi, homes had access to water from wells. Bathing rooms directed wastewater into covered drains along main streets. Homes opened to inner courtyards and smaller lanes. Some village homes today still look similar to those of the Harappans.
Indus Valley cities had advanced drainage and sewer systems, which archaeologists describe as well-planned and more advanced than many other ancient societies. Their buildings included docks, storage areas, brick platforms, and large walls, which may have protected against floods and attacks.
The purpose of the citadels in these cities is still debated. Unlike Mesopotamia and ancient Egypt, which built large monuments, no clear evidence of palaces or temples has been found. Some structures may have been storage buildings. One famous example is the "Great Bath," which might have been a public bath. While citadels had walls, it is unclear if they were for defense or flood protection.
Most people in the cities were likely traders or artisans who lived in neighborhoods with others who had similar jobs. Materials from faraway places were used to make seals, beads, and other items. Artifacts found include glazed faience beads and seals with images of animals, people, and undeciphered writing.
Although some homes were larger, Indus Valley cities were notable for their relative equality. All homes had access to water and drainage, suggesting a society with limited wealth differences.
Archaeologists do not know for certain who ruled the Harappan cities or how. However, evidence shows complex decisions and large-scale resource use. For example, cities were built in uniform grid patterns, and large public projects were constructed, indicating planning authority. The consistency of weights and measures, seen in pottery, seals, and bricks, suggests a central authority that set rules.
Some major theories:
Copper was common at Indus sites, as shown by archaeology. Brett Hoffman’s 2019 study of Harappan copper found that copper and bronze were used in many items, including tools and decorative objects. Copper was alloyed with tin, arsenic, and lead. Copper sources included Rajasthan, Oman, and Bahrain. A gold-testing tool found in Banawali suggests people tested gold purity, a method still used in some parts of India. Recent research shows that access to copper and bronze was widespread, not limited to elites.
The Indus Valley people had highly accurate systems for measuring length, mass, and time. They used a uniform system of weights and measures. The smallest unit, found in Lothal, was about 1.704 mm, the smallest recorded on a Bronze Age scale. They used a decimal system for measurements, including weights shaped like hexahedrons. Weights followed a ratio of 5:2:1, with units similar to the English ounce or Greek uncia. These systems influenced later Indian texts, such as Kautilya’s Arthashastra from the 4th century BCE.
Late Harappan
Around 1900 BCE, signs of a slow decline began to appear, and by about 1700 BCE, most cities were abandoned. Studies of human bones from Harappa in the 2010s showed that the end of the Indus civilization was marked by more violence between people and an increase in diseases such as leprosy and tuberculosis.
Historian Upinder Singh said, "The late Harappan period shows a breakdown of city connections and the growth of rural areas."
Between 1900 and 1700 BCE, several new cultures developed in the Indus region. The Cemetery H culture was found in Punjab, Haryana, and western Uttar Pradesh. The Jhukar culture was in Sindh, and the Rangpur culture, known for its shiny red pottery, was in Gujarat. Other late Harappan sites include Pirak in Balochistan, Pakistan, and Daimabad in Maharashtra, India.
The largest late Harappan sites were Kudwala in Cholistan, Punjab; Bet Dwarka in Gujarat; and Daimabad in Maharashtra. These were smaller and fewer than the earlier large cities. Bet Dwarka had walls and stayed connected to the Persian Gulf, but long-distance trade declined overall. At the same time, farming changed, with more types of crops grown and the use of double-cropping. People also moved their homes more toward the east and south.
Pottery from the late Harappan period shows some similarities to earlier styles but also has new differences. Many places remained occupied for centuries, but cities became less organized. Items like stone weights and small statues of women became rare. Some circular seals with geometric designs were used, but they lacked the writing system of the earlier Harappan period. Writing was rare and only found on broken pottery. Trade over long distances decreased, but local cultures developed new skills in making glass, faience, and carved beads. City features like drains and public baths were no longer maintained, and newer buildings were poorly made. Stone statues were destroyed, and valuables were hidden, suggesting unrest. Animal and human remains were sometimes left in the streets or abandoned buildings.
By the later half of the 2nd millennium BCE, most late Harappan settlements were abandoned. Later cultures were marked by temporary camps and simple handmade pottery, suggesting a nomadic, farming-based population. However, some areas in Punjab, Haryana, and western Uttar Pradesh showed continuity between late Harappan and later cultures, mainly in small rural villages.
In 1953, Sir Mortimer Wheeler suggested that the arrival of Aryans from Central Asia caused the decline of the Indus civilization. He pointed to 37 skeletons found in Mohenjo-daro and references in the Vedas to battles and forts. However, scholars later rejected this idea because the skeletons were from after the city was abandoned and none were near the citadel. Later studies by Kenneth Kennedy in 1994 showed that the skull marks were caused by erosion, not violence.
In the Cemetery H culture (a late Harappan phase in Punjab), some designs on burial urns resemble symbols from Vedic texts, such as peacocks with hollow bodies and a human figure inside, possibly representing souls, and a hound linked to Yama, the god of death. This may suggest new religious beliefs, but there is no evidence that Cemetery H people destroyed Harappan cities.
Possible reasons for the decline of the Indus Valley Civilization include changes in river courses and climate shifts similar to those in the Middle East. By 2016, many scholars believed that drought and reduced trade with Egypt and Mesopotamia caused the collapse. A major climate change event, a severe drought and cooling 4,200 years ago, may have triggered this, marking the start of the Meghalayan Age.
The Ghaggar-Hakra river system relied on monsoon rains for water. From about 1800 BCE, the climate became cooler and drier, with weaker monsoons. This reduced flooding, making farming less reliable. As water became scarce, people moved eastward. Giosan et al. (2012) noted that Indus Valley residents did not use irrigation and depended on seasonal monsoons. As monsoons shifted south, floods became unpredictable, forcing people to move toward the Ganges basin, where they formed smaller villages and farms. These communities could not support trade, leading to the decline of cities.
Archaeological findings show that Harappa’s decline led people to move east. Possehl noted that between 1900 and 1700 BCE, the number of sites in modern-day India increased from 218 to 853. Andrew Lawler wrote that cities began to appear along the Ganges plain around 1200 BCE, shortly after Harappa was abandoned. Jim Shaffer said that cultural changes in South Asia were continuous, linking the two major urban periods in the region.
At Bhagwanpura in Haryana, excavations found that late Harappan pottery overlapped with early Painted Grey Ware pottery, associated with the Vedic culture (around 1200 BCE). This site shows different groups living in the same village but using different pottery and housing styles. Over time, late Harappan pottery was replaced by Painted Grey Ware pottery, and new cultural changes included the use of horses, iron tools, and new religious practices.
Another Harappan site, Rojdi in Saurashtra, was excavated by an archaeological team from Gujarat and the University of Pennsylvania in 1982–83. Their report noted that while there was cultural continuity between the Harappan civilization and later South Asian cultures, many aspects of the Harappan society and organized civilization were lost. The second major urban period in India, beginning with the Northern Black Polished Ware culture around 600 BCE, developed separately from these earlier changes.
Post-Harappan
Scholars once thought that the decline of the Harappan civilization caused a stop in city life in the Indian subcontinent. However, the Indus Valley Civilization did not end quickly, and many aspects of the Indus culture appeared in later societies. The Cemetery H culture may represent the Late Harappan period across areas like Punjab, Haryana, and western Uttar Pradesh, while the Ochre Coloured Pottery culture followed it. David Gordon White mentions three other scholars who have shown that parts of the Vedic religion may have roots in the Indus Valley Civilization.
By 2016, archaeological findings suggested that the Late Harappan material culture may have lasted until around 1000 to 900 BCE, overlapping in time with the Painted Grey Ware culture. Harvard archaeologist Richard Meadow notes that the Late Harappan settlement of Pirak was continuously occupied from 1800 BCE until the arrival of Alexander the Great in 325 BCE.
After the Indus civilization became more localized, regional cultures developed, showing some influence from the Indus civilization. In the former city of Harappa, burials have been found that match a regional culture called the Cemetery H culture. At the same time, the Ochre Coloured Pottery culture spread from Rajasthan into the Gangetic Plain. The Cemetery H culture is the earliest known example of cremation, a practice common in Hinduism today.
People from the Indus Valley Civilization moved from the river valleys of the Indus and Ghaggar-Hakra toward the Himalayan foothills of the Ganga-Yamuna basin.
Genetics
In 2019, a study by Shinde et al. examined a genome rebuilt from DNA found in the bones of a female skeleton discovered in a cemetery linked to the Indus Valley Civilization (IVC) in Rakhigarhi, Haryana, India. The skeleton is estimated to be about 2,800–2,300 BCE. The study found that most of the genome was similar to that of Mesolithic Iranian hunter-gatherers, who lived in Iran during the Mesolithic period and relied on hunting and gathering for survival. A smaller part of the genome matched the ancestry of the Andamanese Hunter Gatherers, a group believed to represent the Ancient Ancestral South Indian (AASI) population, which was indigenous to South Asia. The genome did not include ancestry related to the Western Steppe Herders, a group found in many modern South Asians, especially in northern regions, or ancestry from Anatolian Neolithic farmers. The genetic makeup of the IVC-related individual is similar to the main ancestry of most modern South Asians. Some evidence suggests the possibility of matrilocality, a practice where families lived near the mother’s home, but this remains debated.