Read the given source carefully and answer the questions that follow:
Harappan Settlements
So far, more than 2000 Harappan archaeological sites have been discovered in the Indian sub-continent. Most of the sites are found located between the Indus and the Saraswati River basins. Nearly two-thirds of these settlements are in the Saraswati basin, suggesting its immense importance for the Harappan Civilisation. Among these, five major cities have been identified. These are Rakhigarhi, Mohenjodaro, Harappa, Dholavira and Ganweriwala. The remaining sites come under different categories such as Regional Centres, agricultural villages, ports and manufacturing centres.
Examine the importance of classifying Harappan sites.