THE INDUS VALLEY CIVILIZATION COLLAPSES
The Indus Valley Civilization (c.3300–c.1700 bce) was based around large cities with planned streets and impressive drainage and water-supply systems in what are now Pakistan and northwestern India. By 1900 bce, this civilization was in decline and no longer producing the elaborate jewelry and fine seals for which it was famous. By c.1700 bce, the great Indus cities of Harappa and Mohenjo-Daro were virtually empty. The reason is unclear, but the most likely explanation is a combination of crop failure and a decline in trade with Egypt and Mesopotamia. There is also some evidence of flooding due to a change in the course of the Indus River.