Submitted by Manzoor
I don't think that there was a single cause of the Indus civilization's end; rather it was the cumulative effect of a number of factors:
- Environmental 1 – the progressive decrease in water flowing along the Saraswati system caused the decline and abandonment of many settlements in what had probably been one of the major regions of agricultural production, and possibly the most important one. The drying up was probably triggered early in the second millennium BC by tectonic activity in the Himalayas, altering the course of one of the main rivers feeding the Saraswati system and was exacerbated later when the Indus captured the Sutlej, the other major feeder of the Saraswati system, though this was in Post-Harappan times.
- Environmental 2 – sea levels fell in the late 3rd millennium, disrupting the established network of ports on the Makran coast; in Gujarat, sealevel fall was combined with alluviation at the mouth of the Indus and other rivers. The impact of these changes is unknown: the establishment of a new port at Bet Dwarka suggests that the locals found ways of coping.
- Economic – displaced people from the Saraswati system began to settle further east, loosening their political ties with the Indus heartland. This eastward spread was greatly facilitated by the cultivation of rice, which was beginning to take off, since rice was better suited to the eastern region than the wheat and barley that were Harappan staples. Similarly in the west, the cultivation of millets was encouraging the growth of population in Gujarat and in adjacent regions that had been outside the Harappan realm but within its sphere of influence. This also helped to weaken the political coherence of the Harappan state.
- External 1 – the end of the 3rd millennium BC was a time of significant decline in the Near East, for a variety of environmental, economic and political reasons. This had a knock-on effect on the volume and nature of Mesopotamia's trade through the Gulf. The decline of a major trading partner presumably affected Harappan trade; although it is still unclear what the Harappans got out of trade with Mesopotamia, being unable to obtain the required quantities of Mesopotamian goods must have had some consequences.
- External 2 – the rise of the BMAC and its southward spread into eastern Iran and the Indo-Iranian borderlands presumably was disruptive to Harappan trade into Afghanistan and to its communications network in Baluchistan, even though direct BMAC involvement in the Indus region and beyond did not occur until after the Indus civilization began to fall apart.
- Health – urbanism, bringing large numbers of people into close proximity, encourages the spread and maintenance of endemic diseases. There is evidence from the bones of people from the later levels at Mohenjo-daro that malaria was endemic there. It is probable that cholera was also rife, since there was likely to have been seepage between the drinking water and sewage systems. Poor health in the centres of administration would have had a deleterious effect on the Harappan bureaucracy and political control.
In my recent book, Chapter 2, I discuss the many different opinions about environmental changes and their causes. There are many different opinions about environmental change. At the end of that chapter I present evidence from my own research on a dried up river bed near Harappa. Research my team and I conducted indicates that there was a period that was drier than it had been previously and when there was a lower amount of river discharge, which would have made an impact on the flood waters on which they depended. I suggest there some ideas about how the Harappans reacted to that situation, coming out in the end with the idea that people at that time were very aware of the changes that were taking place and took positive action. At Harappa that meant that they were able to sustain their urban culture, though there were MAJOR changes, diminished populations, absence of the administrative technology (stamps seals, weights, etc.). All that needs to be worked out for other areas; to resolve the discrepancies in the opinions about climate change and different evidence when you look at the larger Indus territory, I suggested this question can only be resolved with the collection of LOCAL data for each region and then come together and discuss the larger territory
I do not believe in the idea of COLLAPSE as inevitable, nor find that word precise enough. It was a transformation. The idea of the collapse of civilization is an old one based on a lack of the kind of evidence we now have worldwide.I am speaking specifically of the notion that it is inevitable that societies rise and fall. We can demonstrate now that it just isn’t the case.
It transformed, but why is still unclear. Cities were downsized or abandoned,, smaller sites were abandoned or located elsewhere, cultural practices and the related iconography changed, some technologies continued, others did not, etc. There are any number of possible explanations: climate change, river shifts, epidemics in crowded cities, increasing insecurity, pressure from pastoralists, revolt, ideological change, etc.. There may not have been a prime mover, but a combination of pressures and events that led to a changed configuration of settlements on the Indus alluvium and adjoining areas. This remains one of the big questions of the archaeology of NW South Asia.
We are dealing with a civilization—which encompassed a large region (i.e., something larger than a regional culture.) The end is manifest in the desertion of a very high proportion of the settlements—including the largest towns. This gives people the idea that some kind of natural disaster eliminated the population.
But there are settlements in the centuries after the bronze age, in the Divide (the plain between the Sutlej and the Jumna systems). And in this north-eastern area, some elements of the local Sothi/Siswal culture are manifest. So it is very likely that there was a shift of population north-eastward. For some reason, urban life ceased to be viable on the greater Indus plain.
It was an integrated, coherent, civilizational system that came to an end: with its characteristic seals, writing, weights, long carnelian beads, urban house architecture, brick-lined wells, etc. What did this system comprise of? There were urban centres, citadels at many of them, large centres much larger than those of the mean size. There were fortifications at citadels and of small sites such as Surkotada and Sutkagen-dor, Bagasra and Shikarpur.
There was clearly a political institution that mobilized mass labour for the production and firing of millions of bricks to build Mohenjo-daro in baked brick.
The weight system, represented at more than a score of Harappan sites, could only mean a regulating authority and supervision of the quantification of certain things—which in turn tells us that certain goods were now becoming commodities.
So it makes sense to suggest that it was the institutions of a bronze-age state that came to an end—and thus, the instruments of that state. Society reverted to villages and rural life. In anthropology a clear connection has been made between the growth of the state and the emergence of urban centres. The latter cannot develop without the former. So we have to consider the collapse of a state system that gave various settlements, large and small, their coherence.
Why and how did such a collapse come about? There could be political or administrative factors (poor development of law-and-order institutions, or of the armed force of the rulers, or an overstretched state reaching over a huge area). In particular localities, the building of platforms, the use of charcoal to fire bricks and for metallurgy, etc. could have disturbed the upper levels of the soil and its rainwater absorbing capacity, or caused local deforestation. There were no temples as built houses of specific gods, as far as we can tell: which would mean the absence of a tutelary deity and its household (priestly personnel) to keep people together in common worship. This could have made the abandonment easier than if there were divinities and their personnel through which a community was attached to a particular locus.