A new study suggests that "megacities" of the Indus Valley region of Pakistan and north-west India may have collapsed because of an ancient episode of climate change.
Investigation demonstrates that the Bronze Age 'megacities' of the Indus Valley region declined during the 21st and 20th centuries BC and never recovered - because of a dramatic increase in drought conditions, the Independent reported.
The research, carried out by the University of Cambridge and India's Banaras Hindu University, reveals that a series of droughts lasting some 200 years hit the Indus Valley zone - and was probably responsible for the rapid decline of the great Bronze Age urban civilization of that region.
The findings correlate chronologically with drought evidence found over recent years by other scientists who have examined deposits from the bottom of the Arabian Sea and the Gulf of Oman as well as stalactites from caves in North east India and southern Arabia.
It's now thought likely that the droughts at around that time were partly responsible for the collapse not only of the Indus Valley Civilisation, but also of the ancient Akkadian Empire, Old Kingdom Egypt and possibly Early Bronze Age civilizations in Greece.
The scientists studying the collapse of the Indus Valley Civilization obtained their new evidence from a dried-up lake bed near India's capital New Delhi which is just 40 miles east of the eastern edge of the Indus Valley Civilisation.
They detected the climatic conditions by examining isotopic evidence from the shells of snails that had lived between 6500 years ago and 1500 years ago.
The new research is reported in the journal Geology.
