The death of a civilization rarely has a single cause. It is always the convergence of several fragilities that combine and amplify each other. For the civilization of the 7 Rivers, this convergence is today documented with remarkable precision — by geology, tectonics, hydrology, climatology and archaeology. And at the heart of this collapse, there is the disappearance of a river.
The Sarasvatī — the greatest, the most sacred of the seven rivers — ceased to flow around 1900 BCE. And with her, a civilization of several million inhabitants had to reorganize, migrate, and progressively transform into something else.
The Sarasvatī at the height of her glory
To understand what the disappearance of the Sarasvatī represented, one must first understand what she was.
In The Civilization of the 7 Rivers, I describe her as the principal river of the civilization — the one the Rig Veda calls “best of rivers,” the one the rishi Vasiṣṭha sings in hymn 7.95 as “surpassing all the waters of other rivers.” She descended from the Himalayas, crossed the plains of Punjab and Rajasthan, and flowed into the Arabian Sea.
On her banks stood some of the greatest cities of the civilization: Rakhigarhi — probably the largest, whose recent excavations suggest it exceeded Mohenjo-Daro in area — Kalibangan, Banawali, Ganweriwala. The Sarasvatī was the main artery of an urban network that counted hundreds of cities and thousands of villages.
Her real magnitude was revealed by satellite remote sensing. Yash Pal and his colleagues at ISRO, in their founding 1980 article (Remote Sensing of the ‘Lost’ Sarasvatī River, Proceedings of the Indian Academy of Sciences), showed that satellite images reveal a dried-up bed several hundred metres wide — in some areas, up to eight kilometres. This was a river comparable to the Ganges or the Indus in their Himalayan phase.
The dual cause: tectonics and climate
In The Civilization of the 7 Rivers, I document this with scientific sources: the drying up of the Sarasvatī is the result of the combination of two independent factors, which acted at different rhythms but combined in a catastrophic way.
The tectonic factor
Earthquakes are very frequent in the Himalayas — one of the most seismically active zones in the world, the result of the ongoing collision between the Indian and Eurasian plates. These earthquakes have considerable effects on the region’s hydrological network.
In The Civilization of the 7 Rivers, I note that the Sarasvatī was fed by two major tributaries: the Dṛṣadvatī, which itself received the Yamunā, and the Shutudrī (the modern Sutlej). Geologist R. Rajaram documents that Himalayan earthquakes progressively diverted the courses of these tributaries:
“Geological evidence suggests that the Sarasvatī River, a major river in the northwestern part of the Indian subcontinent, began to dry up around 1900 BCE, probably due to tectonic shifts and changes in monsoon patterns.”
The Yamunā was diverted eastward — toward the Ganges — at a Himalayan fault that Indian geographers have identified as “the tear of the Yamunā.” This diversion deprived the Dṛṣadvatī of its principal tributary. The Dṛṣadvatī dried up — its bed is still visible today, now called the Chautang. The Shutudrī was diverted westward, joining the Indus rather than the Sarasvatī.
Deprived of her two great Himalayan tributaries, the Sarasvatī was fed only by local sources and monsoon waters — insufficient to maintain a great river in year-round activity.
The climatic factor
Simultaneously, the region suffered a major drought around 2200 BCE — a global climatic event documented on several continents, probably linked to a disruption of atmospheric circulations in the North Atlantic.
In The Civilization of the 7 Rivers, I formulate it thus: a major climatic disruption occurred around 2200 BCE — a period of drought that, according to various studies, could have lasted from ten years to a century. Remarkably, Sumerian commercial archives show no sign of a decline in Meluhha exports during this period — the 7 Rivers civilization continued to export normally. This suggests that the first phase of the crisis did not immediately affect agricultural production, but progressively weakened water resources.
The convergence and its consequences
The combination of these two factors — tectonic diversion of tributaries and reduced monsoon precipitation — had cumulative devastating effects on the Sarasvatī.
Between 2200 and 1900 BCE, the river progressively diminished. The cities on her banks first adapted their agricultural practices. Then, when the Sarasvatī became insufficient to feed dense urban populations, the migrations began.
The population did not disappear. It migrated — first to the Indus Valley, but the Indus cities, already populated, were quickly overwhelmed by these migratory flows. Then to the Gangetic plain, to Gujarat, to Rajasthan. In The Civilization of the 7 Rivers, I note: this migration appears to have occurred without violence or destruction — the archaeological sites show no trace of fire, no precipitous abandonment, no bones bearing marks of violence.
This was a slow retreat, not a flight.
What the experts say
Michel Danino, whose book The Lost River: On the Trail of the Sarasvatī (Penguin Books India, 2010) is the most complete reference on the subject, formulates it thus:
“The drying up of the Sarasvatī River, which is believed to have occurred around 1900 BCE, marks a significant transformation of the landscape of northwest India, influencing the migration patterns of the Harappan civilization.”
And David Frawley:
“Around 1900 BCE, the Sarasvatī River, once a major river system in Vedic times, began to dry up, profoundly affecting the civilizations that thrived along its banks.”
The river rediscovered by satellites
Today, the dried-up bed of the Sarasvatī is clearly visible — on the ground, in satellite images, in toponymy. The Ghaggar river in India and the Hakra in Pakistan follow the ancient course. They still flow a little during the monsoon, seasonally. They therefore have something extraordinarily moving about them: they still exist, diminished, reduced to a shadow of their former glory.
And on their banks, excavations continue to reveal new sites of the 7 Rivers civilization. Rakhigarhi, excavated since 2014, may well become the most important site of the entire civilization — larger than Mohenjo-Daro, larger than Harappa.
The Sarasvatī has disappeared. The civilization she carried still speaks to us.
