A new scientific study analyzing stalagmites from a cave in the Himalayas has provided a high-resolution timeline for the megadrought that contributed to the decline of the Indus Valley Civilization. By measuring oxygen isotopes, researchers identified a 200-year period of significantly reduced monsoon rainfall starting around 4,200 years ago.
This data corroborates the '4.2k event' seen globally, but offers specific insights into how the Harappans attempted to adapt by shifting to more drought-resistant crops like millet. The research highlights the critical role of climate change in the transformation of ancient urban societies into smaller, rural settlements.