Revisiting the contemporaneity of a mighty river and the Harappans: Archaeological, stratigraphic and chronometric constraints

The role of major northwestern Indian rivers in sustaining the Harappan civilisation has been a much-debated topic in Indian archaeology. Reconstruction of palaeo-river courses using remote sensing images and their association with the mighty rivers (viz. Sarasvati and Drishadvati) mentioned in ancient Indian literature, has long been contested. The relationship of these rivers to the Ghaggar and Chautang channels, believed to be the former course of the glacially fed Sutlej and Yamuna rivers respectively, has also been debated. A mighty river of glacial origin has been hypothesised to have sustained the Harappan civilisation, and yet the spatial and temporal associations between palaeo-river courses and the Harappans are poorly understood. We provide new quartz optically stimulated luminescence dates from stratigraphically controlled samples from the palaeo-river bed and adjacent floodplain of the Chautang River near Hissar in Haryana, to elucidate the timing of glacially derived fluvial activity and examine its synchronicity with the Harappan cultures. Our results disprove the proposed link between ancient settlements and large rivers from the Himalayas and indicate that the major palaeo-fluvial system traversing through this region ceased long before the establishment of the Harappan civilisation. These results are further corroborated through a review of archaeological data to assess the spatial and temporal variation in the abundance of Harappan sites along a perennial and ephemeral riverine corridor. This synthesis of archaeological data also urges caution over the linear association of the number of ancient settlements with the strength of rivers.