The Indus valley civilization is believed to belong to the copper stone age as the presence of iron tools and implements has not yet been established at any part of this civilization. 

Archaeological excavation indicates that the Indus valley civilization could have flourished in about  300 BC much before the existence of other West Asian civilization. Contacts with the civilization of Mesopotamia, Elam and Babylon can be deduced by the discovery of the Indus valley clay seals, pottery there. This suggests that  the civilization flourished from about 3000 BC to 1500 BC.

Anthropological investigation and examination of the human remains shows that four racial types existed in this civilization. They were the proto - Australiod, Mediterranean, Alpine and the Mongoloid. Archaeological excavation reveal the existence of various racial types. Of all these the existence of the Dravidian race holds its relevance owing to its wide spread acceptance. 

Decline of the Indus Valley Civilization

The Indus valley culture though existed in its modern form else where it had to submit to the ultimate ravages of time which is the universal law. The physical existence of the civilization ended due to various factors.

(a) Changes in the climate leading to the decline of land and agriculture, thereby enforcing the need to evacuate to other area might have been the reason for the dissertation of the Indus valley.

(b) Increase in population, excessive deforestation decline in agriculture etc might have created economic problems leading to the gradual decay of the culture. 

(c) Frequent floods may have led to the devastation of the city 

(d) The invasion of the Aryans is the other view that is said to be another reason which might have also led to the extinction of the life in the Indus valley.

The Indus valley civilization has put India at par with the other civilization of the world, which is  said to be the foundation on which the present cultures of  nations are built.