Climate reconstructions suggest repeated droughts slowly reshaped one of the world’s earliest urban societies.

Around 5,000 years ago, the Indus Valley Civilization emerged as one of the world’s first advanced societies, spreading across what is now Pakistan and northwest India. Its cities featured planned streets, advanced drainage systems, and wide-ranging trade that rivaled ancient Egypt and Mesopotamia.
By about 3,900 years ago, however, the civilization began a long transformation that reduced its major cities and dispersed its population.
New scientific research suggests this change was driven not by sudden collapse, but by centuries of recurring drought that steadily strained water supplies, agriculture, and urban life.








