Discovery and the archaeogenetic turn

Detail

Early false starts

• 1875: Alexander Cunningham reports a Harappan seal but cannot place it chronologically — he expected Indian history to begin with Ganga-valley cities and worked off itineraries of Chinese Buddhist pilgrims (Xuanzang/Faxian), a framework with no room for a pre-Vedic urban civilisation.
• Harappa's mound was already damaged by brick robbers: Cunningham noted enough Harappan brick had been quarried to lay ~100 miles of the Lahore–Multan railway track ballast. Mohenjo-daro escaped this and preserved stratigraphy far better.

The 1920s breakthrough

• 1921: Daya Ram Sahni begins systematic excavation at Harappa (Punjab).
• 1922: Excavations start at Mohenjo-daro (Sindh); R.D. Banerji recognises seals matching Harappa's, establishing the two sites belonged to one culture.
• 1924: John Marshall, Director-General of the Archaeological Survey of India (in post 1902–1931), announces discovery of a new civilisation to the world. Marshall was the ASI head who directed this phase of large-scale excavation [2]. Contemporaneity with Mesopotamia was established by cross-matching Harappan seals found in Mesopotamian excavation layers — leading to Marshall's remark that the find "left India three thousand years older than he had found her."
• 1931: First official excavation report on Mohenjo-daro published, including a dedicated section on the (still undeciphered) Indus script [2].

Post-1947 method shift and site geography

• 1946: Mortimer Wheeler excavates at Harappa, introducing stratigraphic (vertical, layer-by-layer) excavation — correcting Marshall's earlier horizontal, area-clearing method that had blurred chronological layers.
• 1955: S.R. Rao excavates Lothal (Gujarat).
• 1960: B.B. Lal and B.K. Thapar excavate Kalibangan (Rajasthan).
• 1990: R.S. Bisht excavates Dholavira (Gujarat).
• 1997 / 2013: Amrendra Nath excavates Rakhigarhi (Haryana); reinvestigated from 2013 with Vasant Shinde's archaeogenetics programme.
• Driver of the post-Partition shift: Harappa and Mohenjo-daro, the two type-sites, fell in Pakistan after 1947. Indian archaeology responded with a fresh search inside Indian territory, yielding Kalibangan, Lothal, Rakhigarhi, and Dholavira as the major domestic sites.

The Rakhigarhi archaeogenetic turn

• Shinde et al., Cell (2019), as presented in the NCERT chapter: aDNA from Rakhigarhi skeletal remains shows Harappans were indigenous to South Asia, with genetic roots traceable to c. 10,000 BCE.
• Finding of continuity: present-day South Asian populations carry substantial genetic descent from this Harappan population, with only small admixture attributable to trade contacts rather than mass migration.
• NCERT reads this as evidence against a large-scale "Aryan" immigration event.
• 3D facial reconstructions from Rakhigarhi skeletal material were found to resemble the present-day population of Haryana.

• Note: the NCERT chapter itself explicitly flags the Harappan–Vedic relationship as an open question requiring further research — this should be presented as the textbook's stated position, not as settled academic consensus. Independent genetic literature on steppe-ancestry timing remains actively debated outside the NCERT framing.

Method notes (mains-usable)

• Stratigraphy: lowest layers = oldest occupation; sterile (artefact-free) layers signal site abandonment.
• Classification: objects grouped by raw material and by inferred function.
• Interpretation techniques: analogy with present-day objects/practices; attention to find context (house floor, drain, grave, kiln — same object type means different things in different contexts); indirect inference (e.g., cotton fibre traces + a sculpture in fitted cloth → evidence of woven cotton clothing).
• Evidentiary caution: only objects that were broken, lost, or deliberately hoarded/buried survive archaeologically — the surviving record is accidental, not representative of everyday typical use.
• Open questions flagged in NCERT: the undeciphered script; the actual function of the Great Bath at Mohenjo-daro; extent of literacy across society; unusually low differentiation in burial/cemetery goods (limited evidence of stark social hierarchy); division of labour/gender roles in craft production.

Prelims Hooks

• Cunningham (1875) first reported a Harappan seal but failed to date it — expected history to start with Ganga-valley cities.
• Daya Ram Sahni excavated Harappa (1921); R.D. Banerji worked Mohenjo-daro (1922).
• John Marshall announced the civilisation in 1924; dating via seal parallels found in Mesopotamian excavations.
• Wheeler (1946) introduced stratigraphic excavation at Harappa, superseding Marshall's horizontal method.
• Harappa's original mound was damaged by brick-robbing for the Lahore–Multan railway.
• Site–excavator pairs: Lothal–S.R. Rao (1955); Kalibangan–B.B. Lal & B.K. Thapar (1960); Dholavira–R.S. Bisht (1990); Rakhigarhi–Amrendra Nath (1997), later Vasant Shinde.
• Rakhigarhi aDNA study published in Cell (2019), led by Vasant Shinde.
• Rakhigarhi genetic study indicates Harappans were indigenous, with lineage traceable to c. 10,000 BCE.
• Marshall was ASI Director-General from 1902–1931; first official Mohenjo-daro excavation report published 1931 [2].

Mains Points

• Discovery timeline (1875 misreading → 1924 announcement) illustrates how a prevailing historiographic paradigm (Ganga-valley origin thesis, pilgrim-itinerary framework) delayed recognition of an older, independent urban civilisation — a caution on how method/assumption shapes discovery.
• The Marshall→Wheeler transition (horizontal digging → stratigraphy) is a standard GS-I example of methodological evolution in archaeology improving chronological precision.
• Rakhigarhi aDNA findings feed the Aryan migration vs indigenous development debate — usable as evidence in the Vedic-Harappan continuity/discontinuity debate, while NCERT itself cautions the relationship needs further research (avoid overstating settled-ness in an answer).
• Post-1947 site geography (major sites in Pakistan) explains why Indian archaeology's post-Independence effort (Kalibangan, Lothal, Rakhigarhi, Dholavira) became central to reconstructing Harappan civilisation from within Indian territory — link to broader theme of Partition's effect on heritage/archaeological access.