Why don't people have more information about the Indus Valley civilization?

Responses

only one ancient city in the Indus Valley has been discovered and explored

only one ancient city in the Indus Valley has been discovered and explored,

archaeologists and historians have been unable to decipher the Indus Valley writing

archaeologists and historians have been unable to decipher the Indus Valley writing,

most archaeologists and historians prefer to work on the Mesopotamian and Egyptian civilizations
most archaeologists and historians prefer to work on the Mesopotamian and Egyptian civilizations

the ancient people of the Indus Valley purposely obscured evidence of their existence

the ancient people of the Indus Valley purposely obscured evidence of their existence