A section from the journey

When the Rivers Changed

After about 1900 BCE the great cities slowly emptied. The writing fades, the trade fades, the people scatter into smaller villages and drift east toward the Ganga plains. Why? Not a sudden disaster, but the land itself changing. The rains weakened, and the rivers that fed the cities faltered. This was a long, slow transformation, not a dramatic death.

Every great thing has its morning, its noon, and its evening. We have walked the cities at their height. Now, gently, we come to their evening. It is not a tale of horror, and we should not tell it as one.

From about 1900 BCE, the signs of city life begin to fade. The little seals appear less often. The far-off trade with distant lands thins out. The careful standard weights fall out of use. One by one, the marks of the great urban world grow faint.

But mark this well, for it matters. The people did not vanish. They did not die in fire and sword. They moved. They spread out from the crowded cities into smaller villages, and they drifted slowly east and south — toward the plains of the Ganga and the Yamuna, and into the land we now call Gujarat. The crowd thinned, and the way of life changed. That is a very different thing from a sudden death.

So what turned the cities' noon toward evening? For a long time, people guessed at some sudden disaster. But the answer scholars now find is quieter, and in its way sadder. The land itself changed.

Think of where these cities lived: by rivers, in a land where the summer rains, the , brought the water that fed the fields. Over long centuries, those rains weakened and shifted to the east. The rivers that had watered the dry country began to falter. Studies of the old riverbeds and the ancient climate tell this story clearly.

One river matters most of all. The , along whose banks the thickest band of cities and villages had grown, dried until it ran only in the wet season, or not at all. Take away the water, and you take away the fields. Take away the fields, and a great city cannot feed its crowds. So, slowly, the people followed the water to where the rains still fell.

There were likely other strains too — shifting river courses, the fading of distant trade. But the heart of it was the changing land and the failing water. Many scholars no longer even like the harsh word "collapse." They speak instead of transformation: a way of life that did not end, but bent, scattered, and moved, carrying its threads forward into the ages to come.

There is an old, dramatic story that an invading people destroyed these cities by the sword. We will look at that story closely in our next sitting, and see why scholars on every side now set it aside. For now, hold the gentler truth: the rivers changed, and the people moved. Hold, too, a quiet feeling we will meet again far down our road — that all things rise, and flourish, and pass, and turn. The cities knew that turning.

The rishi steps to the Threshold — where accounts differDid incoming peoples end the Indus cities, or did the cities decline as the climate and rivers changed?

What scholars find

The mainstream scholarly view is that the cities declined chiefly because the climate and rivers changed, not because of any invasion. Studies such as Giosan and colleagues' work on the old riverbeds find that the summer monsoon weakened and shifted eastward over centuries; the rivers of the arid Indus and Ghaggar-Hakra belts, fed by those rains, faltered and in places dried, removing the water base for farming. People dispersed into smaller settlements and drifted east toward the Ganga plains. Scholars such as Shaffer and Lichtenstein describe this as a cultural transformation and eastward shift, not a collapse. Crucially, the Indo-Aryan language associated with the Vedas is dated by most scholars to after the cities had already declined, so the old idea that incoming "Aryans" destroyed the cities is rejected: the timing does not fit, and there is no archaeological trace of such a conquest.

As parts of the tradition hold

Some within the tradition, and some scholars, also reject any invasion-driven end to the cities, and go further. They read the drying of the Ghaggar-Hakra — which they identify with the Vedic river Sarasvati — and the eastward move of the people as part of one long, unbroken life on this land, with no incoming population needed to explain the change at all. In this view, the same people who built the cities adapted to the failing rivers and carried their culture forward in place, so that the Vedic world grows directly out of the Indus world rather than arriving from outside.

It is tempting to want a single villain, one sharp cause, when something great comes to its end. The truth is often slower and kinder than that — a long change no one chose. How does it sit with you, to let go of the dramatic ending and accept the quiet one?