A site of the Indus valley civilisation. (IE)

Researchers at the Indian Institute of Technology (IIT), Kharagpur, have claimed that the Indus Valley civilisation, which saw its doom nearly 4,350 years ago, was a result of a 900-year-long monster drought. As per the report by the Times of India, the widely-accepted theory that a 200-year-long monster drought ended the Indus Valley civilisation may just change by at least seven centuries. Scientists have gathered evidence that proves this theory.

This long drought, as per the report, forced people to abandon their settlements in search of greener pastures and drove them towards the east and south, where rain conditions were better. As per the report, these displaced people gradually migrated towards the Ganga-Yamuna valley towards eastern and central Uttar Pradesh, Bihar and Bengal in the east and Madhya Pradesh, south of Vindhyachal and south Gujarat in the south. The information regarding these findings will be published in the prestigious Quaternary International Journal of Elsevier later this month.

After studying the monsoon’s variability for the past 5,000 years, the researchers from the geology and geophysics department are now certain that for 900 long years, the rains played truant in the North-West Himalayas. This eventually dried up the source of water which fed the rivers along which the civilisation thrived. Archaeologists and historians also found that the Indus Valley civilisation was not only limited to the banks of the Indus but had footprints along the rivers like Ravi, Chenab, Beas and Sutlej as well.

The IIT team has also studied 5,000-year monsoon variability in the Tso Moriri Lake in Leh-Ladakh. The lake was also fed by the same glacial source. The team has identified the periods that had continuous spells of good monsoon as well as the phases of weak and near-no-monsoon. As per the report, the scientists worked over a five-metre deep sediment’s geochemical parameters. These layers revealed the years of good and bad rains. The researchers studied every five-millimetre depth of the sediment layer that indicated a span of eight to 10 years. A total of 520 samples were studied to go back to an antiquity of 5,000 years.