Monsoon decline -- Fall of IVC

Monsoon decline caused rise and fall of Harappan civilisation, say scientists----- N. GOPAL RAJ 

                                 Why did the Harappan civilisation, which flourished for hundreds of years and once extended across a vast area from northwestern India and across Pakistan, suddenly go into a terminal decline some 4,000 years ago and wither away?

                                 Like their script that has remained indecipherable, the question what caused a sophisticated urban culture, capable of great feats of town planning and which had established a trading network that extended across the Middle East, to suddenly collapse is one that has aroused much scholarly debate and writing.

                                  It has been suggested that reduction in water availability, perhaps as a result of climatic change or because tectonic activity caused rivers to change course, could have played a significant part in the decline of this ancient civilisation.

                                 In a paper being published this week in the Proceedings of the National Academy of Sciences (PNAS), a team of scientists from the U.S., U.K., Pakistan, India and Romania has argued that long-term changes in monsoon rainfall altered river flow, creating conditions that initially allowed the Harappan civilisation to thrive but led later to its demise.

                                Liviu Giosan, a geologist, and colleagues have also reconstructed the landscape of the plain and rivers wherein the development of long-forgotten civilization had taken place. "Our research provides one of the clearest examples of climate change leading to the collapse of an entire civilization", he adds.

                                   “After 500 years of flourishing urbanism, the increasing aridification due to a shifting monsoon led to a crisis in the agriculture of the hinterland that supported the cities,” remarked Ronojoy Adhikari of the Institute of Mathematical Sciences in Chennai, one of the authors of the paper. This led to large-scale migrations towards moister regions to the north and a decline in the urban system of the Harappan civilisation.

Counter point ---
                                   This above mentioned Monsoon failure theory is a doubtful correlation. This Monsoon decline theory is absolutely fine,there is no objection to that theory at all. But, only problem is that this monsoon decline theory is being correlated to the fall of Indus Valley Civilization,which is a kind of  illogical correlation.

                                  This theory of " Monsoon Decline" is being stretched beyond a limit to accommodate the theory of "Harappan Decline".  The Indus river is a perennial river and it doesn't dry up even in harsh summers because of the melting of glaciers. The river Indus supports nearly 18 crore people Pakistan even today. Could't it have supported a few thousand people 5000 years back? It looks like that there is some misinterpretation here.
                               Further, the research team is analysing about the sites on the banks of "Saraswathi River", which was supposed to be a seasonal river. But, concludes that IVC sites declined because of monsoon failure, which were on the banks of "Indus River", which is a perennial river. This research team needs fundamental lessons on geography before diving deep into ancient Indian History.. 
                             There is a possibility that IVC never declined at all. These Indus Valley excavation sites are looking deserted because these sites were used as grave yards from time immemorial by various occupants of these lands.These sites have been wrongly identified as Metropolises, whereas in reality they were only Necropolises. This wrong identification is the reason for confusion surrounding  theories like this about IVC. Follow the below given link for detailed information.
-------- Necropolis Theory ----