An IIT Kharagpur study claims that a drought-like phase that lasted for over 900 years ended the Indus Valley Civilisation. Researchers from the Department of Geology and Geophysics reported a new finding on the disappearance of the civilisation, as per a statement from the institute Monday. A team led by Professor Anil K Gupta observed a drought-like phase for a period of 900 years, which led to water scarcity and mass migration to other regions.
The Indus Valley Civilisation covered an area of 1.5 million sq km over India, Pakistan, Baluchistan and Afghanistan. Around 4,200 years ago, the population abandoned its major settlements near the Indus, for the Ganga-Yamuna plains. Diverse theories such as droughts, destruction by floods and foreign invasions, among others, had been debated over the years to explain this.
Professor Gupta along with his team members from Wadia Institute of Himalayan Geology, Dehradun, and Institute of Estuarine and Coastal Research, Shanghai, China studied Tso Moriri Lake situated in Ladakh. It showed that around 4,350 years ago, monsoon weakened under the influence of strong El Niño and southward migration of the inter-tropical convergence zone. This decreased moisture transport and snow deposition in northwest Himalaya, which was a major source of water of the Indus and its tributaries.
“They might have tried to adapt to the situation but this arid phase continued for more than 900 years. Therefore, in search of better water availability for their agriculture and animal husbandry, which were major occupations for the people of the civilisation, they had to migrate to south and eastward regions in India, which were under more influence of the Indian summer monsoon,” said Gupta.