Analysis of sand grains using optically stimulated luminescence by Ajit Singh and others in 2017 indicated that the suggested paleochannel of the Ghaggar-Hakra is actually a former course of the Sutlej, which diverted to its present course before the development of the Harappan Civilisation. The abandonment of this older course by the Sutlej started 15,000 years ago, and was complete by 8,000 years ago. Ajit Singh et al. conclude that the urban populations settled not along a perennial river, but a monsoon-fed seasonal river that was not subject to devastating floods.