The earliest settlement in the subcontinent with evidence of agriculture and domestication at Mehrgarh — now in Pakistan — is about 9,000 years old. This coincides with the peak intensification of the monsoon, the study said... The Arabian Sea sediments and other geological studies show that the monsoon began to weaken about 5,000 years ago. The dry spell, lasting several hundred years, might have led people to abandon the Indus cities and move eastward into the Gangetic plain, which has been an area of higher rainfall than the northwestern part of the subcontinent... About 1,700 years ago, the monsoon began...