Miscellaneous News

Harappan Civilization Decline

August 2 , 2026 9 hrs 0 min 28 0

A study by the Birbal Sahni Institute of Palaeosciences (BSIP) found that a weak Indian Summer Monsoon (ISM) around 4,200 years Before Present (BP) contributed to the decline of the Harappan Civilization.
Researchers analysed pollen records from Deoria Tal Lake, Garhwal Himalaya, to reconstruct past vegetation and climate changes.
The study found that the 4.2 ka event caused a cooler and drier climate, weakening monsoon rainfall and affecting agriculture in the Indus and Ghaggar-Hakra river regions.
Due to reduced river flooding and water availability, Harappan populations migrated towards the eastern Ganga plains.
The study linked the climate shift to factors such as changes in the Inter Tropical Convergence Zone (ITCZ), El Niño, and Indian Ocean Dipole (IOD).