The Indus Valley civilization was comparable to ancient Egypt or Mesopotamia in sophistication.

Evidence

It became clear that this was a land of sophisticated urban centres, trade and industry, and even writing. It must have ranked as a contemporary and an equal with ancient Egypt or Mesopotamia – and it had been totally forgotten. — Neil MacGregor, A History of the World in 100 Objects, 235

Categorization

• XREF: This description could serve as background for articles addressing urban development and trade in ancient history.
• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 235