The Indus Valley Civilization probably didn’t disappear all at once. New research points to a long stretch of repeated droughts that may have slowly weakened one of the world’s earliest urban societies. Cities such as Mohenjo-Daro and Harappa, once built around reliable rivers, appear to have struggled as water became harder to find. As conditions worsened, people began to move away, settlements declined, and everyday life grew uncertain. It’s striking to realize how deeply something as ordinary as rainfall could shape the fate of an entire civilization. Researchers believe the damage unfolded over many decades, with early changes so gradual they may have gone almost unnoticed at first.
How the Indus Valley built smart cities by the river
As cited in ScienceDaily study, titled, ‘Scientists finally uncovered why the Indus Valley Civilization collapsed’, the Indus Valley, also known as the Harappan civilization, was highly advanced for its time. Cities weren’t just heaps of bricks; they had organized streets, complex drainage, and water-management systems. Experts say the society had trade links as far as Mesopotamia. They even developed a script, though we can’t read it today.But life was never entirely smooth. Even with all that clever engineering, the civilization still depended heavily on the Indus River. When the river’s flow changed, the whole system started to wobble. Experts note that climate shifts, particularly rainfall patterns, might have slowly made the area harder to live in.
How long have droughts slowly broken the Indus Valley
Scientists studying this used computer climate simulations spanning thousands of years. These simulations reportedly show rainfall steadily declining between 5,000 and 3,000 years ago. Some droughts apparently lasted more than 85 years at a stretch. That’s a long time without reliable water.It seems that as the droughts dragged on, people moved closer to remaining water sources. Eventually, though, even those areas couldn’t sustain large populations. Cities began to empty. A particularly long drought around 3,500 years ago reportedly coincides with widespread abandonment of major sites. Archaeologists see this as the moment the civilization really started to unravel.
Stone and mud tell the story of the droughts
To check the models, researchers looked at stalagmites and stalactites in regional caves. When growth slows, it usually means less rainfall. They also checked lake sediments. Both seem to match the simulations pretty well. It’s like the environment was leaving a diary, in stone and mud, of exactly what was happening.Nick Scroxton, a climate scientist, reportedly said this work helps explain how changing rainfall influenced urban settlement and agriculture. Liviu Giosan, a geoscientist, called the study “a significant step” in understanding hydroclimate in ancient civilizations. Seems like the scientists were pleased with their cross-checking.
