⚡ Topic 06 of 6 · Chapter 02 · Quick Revision

Decline of IVC & Quick Revision

Theories of decline — Aryan invasion, climate change, floods, tectonic activity. Complete chapter revision checklist.

📉 Decline of IVC (~1900 BCE)

The IVC began to decline around 1900 BCE and had largely disappeared by 1300 BCE. The exact cause of decline is debated — multiple theories exist:

Theory	Proponent	Evidence For	Evidence Against
Aryan Invasion Theory	Mortimer Wheeler, R.E.M. Wheeler	Skeletons at Mohenjo-daro; Rigveda mentions destruction of forts (Indra as “Purandhara”)	No evidence of large-scale warfare; skeletons may be from different periods; Aryans arrived after decline
Climate Change / Drought	Gwen Robbins Schug, Liviu Giosan	Evidence of prolonged drought ~1900 BCE; monsoon weakening; drying of Ghaggar-Hakra river	Most widely accepted today; explains gradual decline
Floods	John Marshall, M.R. Sahni	Evidence of flood deposits at Mohenjo-daro	Floods would cause local, not civilisation-wide decline
Tectonic Activity	R.L. Raikes	Evidence of tectonic uplift blocking Indus drainage	Limited evidence; cannot explain widespread decline
Epidemic / Disease	Gwen Robbins Schug	Evidence of disease in skeletal remains at Rakhigarhi	One factor among many; not sufficient alone
Deforestation & Ecological Degradation	Fairservis	Overuse of wood for brick-making; soil degradation	Gradual process; cannot explain sudden decline

⭐ Current Consensus: Most historians today believe the decline of IVC was caused by a combination of factors — primarily climate change (drought) leading to drying of the Ghaggar-Hakra river, combined with ecological degradation, floods, and possibly disease. The Aryan Invasion Theory is now largely discredited as the primary cause.

✅ Complete Chapter 02 Revision Checklist

✅ Palaeolithic: Crude tools, nomadic, hunter-gatherers; Bhimbetka cave paintings
✅ Mesolithic: Microliths, semi-nomadic; Bagor = largest Mesolithic site
✅ Neolithic: Polished tools, agriculture, pottery, settled life; Mehrgarh = oldest Neolithic site
✅ Chalcolithic: Copper + stone tools; Ahar, Kayatha, Malwa, Jorwe cultures
✅ IVC dates: 2600–1900 BCE (Mature Harappan phase)
✅ Harappa discovered: Daya Ram Sahni (1921); Mohenjo-daro: R.D. Banerji (1922)
✅ Largest IVC site in India: Rakhigarhi (Haryana)
✅ Largest IVC site overall: Mohenjo-daro (Pakistan)
✅ Only dockyard: Lothal (Gujarat)
✅ Dholavira: Largest in India; UNESCO World Heritage Site (2021); water conservation
✅ Kalibangan: Fire altars + ploughed field; Rajasthan
✅ Great Bath: Mohenjo-daro; 12m × 7m × 2.4m; ritual bathing
✅ Drainage system: World’s first planned urban drainage
✅ Standardised bricks: Ratio 1:2:4
✅ Cotton: First cultivated by Harappans
✅ No coins: Barter system; No iron: Bronze Age
✅ Meluhha = IVC in Mesopotamian texts
✅ Pashupati Seal: Mohenjo-daro; three-faced; Proto-Shiva
✅ Dancing Girl: Mohenjo-daro; bronze figurine
✅ IVC script: Undeciphered; ~400-600 signs; right to left
✅ Unicorn: Most common animal on IVC seals
✅ Decline: ~1900 BCE; climate change (drought) = most accepted theory

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