A new environmental study published in Quaternary Science Reviews utilizes high-resolution data from stalagmites in Himalayan caves to reconstruct the paleoclimate of the Indus Valley. The results indicate a 200-year megadrought that began around 1900 BCE, coinciding with the abandonment of major Harappan cities.
The research provides the most definitive evidence yet that climatic shifts, rather than warfare, were the primary driver of the civilization's transformation. The data shows a sharp decline in monsoon intensity, forcing populations to migrate toward the wetter regions of the Ganga-Yamuna Doab.