What happened to the Indus Valley cities?
The Indus cities were at their richest between 2600 and 1900 BC. Between 1900 and 1700 BC, this great civilisation started to fall apart.
Trade with Mesopotamia stopped. Archaeological evidence shows how things got worse. The Great Bath at Mohenjo-Daro was built over. The city mounds got overcrowded. Drains blocked up. Some traders even hid their valuables under the floors of their houses! People stopped repairing old homes. Why did this happen?
Was there a war?
Hindu poems called the Rig Veda (about 1500 BC) describe northern invaders conquering the Indus Valley cities. In the 1940s, archaeologist Mortimer Wheeler (1890- 1976) discovered 39 human skeletons at Mohenjo-Daro. He believed that they were people killed by invaders.
Archaeologists now think this is not true. There is no evidence of war or mass killings. Indus Valley people seem to have been peaceful. If they had an army, they have left few signs of weapons or battles.
It's more likely that the cities collapsed after natural disasters. Enemies might have moved in afterwards.
Floods, famine and disease?
What caused the peaceful, rich and organized Indus civilisation to collapse? Perhaps a river changed course, causing floods in some areas, and droughts (lack of water) in other places. There might have been an earthquake.
If there was an environmentalal disaster cities would have flooded and food crops would have failed. People would have starved and diseases spread. Evidence from skeletons shows that many people died from malaria, a disease spread by mosquitoes.
Perhaps the rulers lost control of their cities. Trade stopped and workshops closed. Drains, streets and houses crumbled.
What was left?
By 1500 BC the Indus Valley civilisation was over. Farmers in the Indus Valley went on living in their villages. Only the cities fell into ruins. Over time wind, rain and floods wore some of the mud-bricks away.
People took away many bricks, so only the city-mounds and a few piles of old bricks were left. That's what the railway-builders and archaeologists rediscovered in the 1800s.
Did parts of Indus Valley culture survive?
The religion of Hinduism seems to have links with the ancient Indus religion. Some Hindu gods are like the gods shown on Indus Valley seals. Indus Valley people believed water was holy, and Hindus believe they are 'purified' in a religious way when they bathe in the sacred River Ganges. The cow and bull are sacred animals in India. Farmers still 'terrace' hills slopes to grow crops, the way Indus Valley farmers did. Many people in India and Pakistan wear jewellery much like that made in Indus Valley cities 4,000 yearsago.
Studying the Indus Valley
The Indus Valley civilisation lasted for over a thousand years, and was at its peak for 500 to 700 years.
Archaeologists are still discovering more about life there. They use radiocarbon tests and other dating methods to see how old artefacts are. They take photos of sites from the air. They carry out field surveys, on the ground, to examine the soil and plant life.
Graves can tell archaeologists a lot. Indus Valley people were buried with clay pots and clay figures, as well as beads. Putting these items in graves may mean that they had a religious belief in an afterlife, in which they could use these belongings again.
Poor people may not have been buried. They may have been burned (cremated) and their remains scattered in the river - just like Hindu funerals in South Asia today.