The dating of glass in the Indus Valley and northern India, between 1900 and 1700 BC suggests that this industry was becoming common in all three reg… - Jonathan Mark Kenoyer

More surveys have revealed large, post-Harappan settlements in the Indus region after the major Indus centres were abandoned. . . . Research . . . is beginning to demonstrate that there really is no Dark Age isolating the protohistoric from the historic period.

The significance of these similarities or dissimilarities should not be taken too seriously since the biological anthropologists themselves caution that this is only a tentative suggestion due to the small sample size of the Late Harappan burials. Generally speaking, the biological evidence does not support any hypothesis involving the movements of new populations into Harappa from outside the Indus Valley during the Harappan or Late Harappan periods.

There is no archaeological or biological evidence for invasions or mass migrations into the Indus Valley between the end of the Harappan Phase, about 1900 B.C. and the beginning of the Early Historic period around 600 B.C.