RAS question
Which modern theory attributes the decline of the Indus Valley Civilization primarily to the drying up of the Ghaggar-Hakra (Saraswati) river system?
Correct answer: (A) Climate change and tectonic shifts theory.
The climate change and tectonic shifts theory attributes the decline of the Indus Valley Civilisation primarily to the drying or diversion of the Ghaggar-Hakra (Saraswati) river system.
Explanation
The climate change and tectonic shifts theory combines two environmental mechanisms: tectonic shifts and a weakening monsoon. The Nature Communications article notes that the Ghaggar-Hakra palaeochannel has been linked with the Saraswati tradition, that the present Ghaggar is an ephemeral river mainly fed by monsoon precipitation, and that the drying of the river forming this palaeochannel has been suggested as a major factor in the decline and abandonment of Indus urban centres in the region. This process is placed around 1900 BCE and connected with movement towards the Ganga-Yamuna plain. The decline model is therefore not a single disaster theory, but an environmental decline model centred on river-system change.
Why the other options are wrong
- (B) Robert Raikes's flood theory explains decline through flooding, not through drying of the Ghaggar-Hakra river system.
- (C) The epidemic theory attributes decline to disease, not to tectonic diversion, aridification, or weakening monsoon conditions affecting a river system.
- (D) The Aryan Invasion theory treats external invasion as the cause, not a modern environmental explanation tied to the Ghaggar-Hakra (Saraswati) palaeochannel.
Concept
The decline of the Harappan civilisation includes modern environmental and palaeoclimate explanations. RAS preparation requires candidates to distinguish older flood, epidemic, and invasion explanations from river-system and climate-based interpretations.