The leading current explanation for the decline of the Harappan civilization emphasises:

Ecological/climatic stress and breakdown of trade and administrative networks

A sudden Aryan invasion destroying the cities

Negotiating the Sources, Food Production and the Indus/Harappa Civilization

Unit I opens the paper the way a historian actually opens a period — not with a story of what happened, but with a question about how we know it. NET tests archaeological, literary and foreign-account sources by name and by method, then moves to the earliest food-producing communities and the Indus/Harappa civilization, India's first cities. This chapter covers sources, pastoralism and Harappa; the next covers the Vedic age and the Mahajanapadas.

1. Negotiating the Sources

Archaeological sources rest on four distinct operations that NET tests separately: exploration (surveying a region for sites without disturbing them), excavation (the actual digging, layer by layer, that recovers structures and artefacts in their stratigraphic context), epigraphy (the study of inscriptions on stone, copper plates and metal) and numismatics (the study of coins — their metal content, weight, legend and find-spot). Dating a site combines relative methods (stratigraphy, seriation of pottery types) with absolute, scientific ones — radiocarbon (Carbon-14) dating for organic remains, thermoluminescence for pottery and burnt clay, and dendrochronology for wood.

Literary and foreign sources: the distinctions NET tests
Category	What it covers
Indigenous literature — primary/secondary	Religious texts (the Vedas, Puranas, Buddhist and Jaina canons) and secular ones (Arthasastra, Sangam poetry) each carry a dating problem — oral transmission across centuries before being written down means a text's own claimed date and its actual composition date can differ widely; myths and legends require separating a kernel of social memory from later elaboration.
Foreign accounts — Greek, Chinese, Arabic	Greek writers (Megasthenes' Indica, known through later citations) describe Mauryan administration; Chinese pilgrim-travellers (Fa-Hien under the Guptas, Hiuen Tsang and I-tsing later) record Buddhist institutions and social observation; Arab geographers and travellers record coastal trade and, later, the Sultanate's own administration.

⚠️ Exploration is not excavation

A question describing a survey that locates and records sites without digging is exploration; a question describing stratified digging that recovers artefacts in context is excavation. Do not conflate the two — NET has asked this distinction directly, and epigraphy/numismatics are the study of a category of artefact (inscriptions, coins) rather than a stage of fieldwork at all.

2. Pastoralism and Food Production: Neolithic and Chalcolithic

The Neolithic phase (roughly 7000-3000 BCE in the Indian subcontinent, earliest in Mehrgarh in present-day Balochistan) marks the shift from hunting-gathering to settled food production — domestication of plants (wheat, barley) and animals (cattle, sheep, goat), polished stone tools, and the first small, mud-built villages. The Chalcolithic phase layers copper tool-use onto this base without displacing stone entirely, and is marked archaeologically by distinctive painted pottery traditions (Ahar-Banas, Malwa, Jorwe) across the Deccan and western India, each with its own regional settlement and exchange pattern.

Settlement and distribution — Neolithic settlements cluster near river valleys and rain-fed uplands (the Kashmir valley, the middle Ganga plain, South India's Neolithic-ashmound sites such as Utnur and Kodekal); Chalcolithic cultures spread across the Deccan and central India with larger, more differentiated villages.
Tools and exchange — polished celts, microliths and, in the Chalcolithic, copper/bronze objects circulate alongside semi-precious stone (agate, carnelian) through networks that anticipate the Harappan trade system that follows.

3. The Indus/Harappa Civilization I: Origin, Sites and Craft

India's first urbanization (Harappan, mature phase roughly 2600-1900 BCE) grew out of earlier regional Chalcolithic cultures (Amri, Kot Diji) rather than appearing suddenly, and covered an enormous extent — from Sutkagen-dor in the west to Alamgirpur in the east, and from Manda in the north to Daimabad in the south, making it geographically the largest of the Bronze Age civilizations. Major sites include Harappa and Mohenjo-daro (Punjab and Sindh), Dholavira and Lothal (Gujarat, the latter with its dockyard) and Kalibangan (Rajasthan, with its distinctive fire altars).

Settlement pattern and craft specialization
Feature	Detail
Citadel and lower town	A raised, walled citadel (public/ritual structures — the Great Bath, granaries) sits apart from a larger lower town of residential blocks, both laid on a grid with north-south and east-west streets — planning is the mark most NET questions test.
Craft specialization	Bead-making (Chanhudaro, Lothal), shell and ivory working, standardized weights (binary system) and a still-undeciphered pictographic script found on seals — the seals themselves (often showing a unicorn-like animal or a horned deity) are craft objects and administrative/trade tools at once.

4. The Indus/Harappa Civilization II: Society, Trade and Decline

Harappan religion is read almost entirely from material remains — seals depicting a seated, possibly proto-Shiva figure, mother-goddess figurines, and the near-absence of monumental temples suggests a religion centred on fertility and possibly ritual bathing (the Great Bath) rather than an institutionalised priesthood on the later Vedic model. Society and polity remain debated precisely because the script is undeciphered: the extreme standardisation across a vast area (weights, brick ratios, town planning) argues for some form of centralised or corporate control, though whether this was a single state, a set of city-states, or a merchant oligarchy is not settled.

Internal and external trade — internal exchange moved raw materials (copper from Rajasthan, semi-precious stone from Gujarat) to craft centres; external trade reached Mesopotamia (Harappan seals found at Ur, and Mesopotamian texts referring to 'Meluhha', widely identified with the Indus region) via the Persian Gulf and Lothal's dockyard.
Decline — no single cause is settled; the leading explanations combine ecological stress (shifting/drying of the Ghaggar-Hakra system, possibly linked to the Sarasvati), climatic change, and the breakdown of the long-distance trade and administrative networks that had held the standardised system together; a sudden 'Aryan invasion' destroying the cities is no longer the accepted account.

ℹ️ First urbanization, and why the number matters

The syllabus names the Harappan phase 'First urbanization in India' precisely to set up the contrast with Unit I's own closing theme, the 'Second Urbanization' of the Mahajanapadas around the 6th century BCE — the two are separated by thé long Vedic period, in which India was not urban at all, and NET regularly tests which urbanization a described feature (baked-brick drains, or iron-tipped ploughs and coinage) belongs to.

Key takeaways

Exploration, excavation, epigraphy and numismatics are four distinct archaeological operations, not stages of one process; absolute dating (radiocarbon, thermoluminescence, dendrochronology) supplements relative stratigraphy.
The Neolithic (domestication, polished tools, first villages) precedes the Chalcolithic (copper alongside stone, regional painted-pottery cultures like Ahar-Banas, Malwa, Jorwe), both feeding into Harappan urbanization.
The Harappan civilization's mark is planning and standardisation — grid streets, uniform weights, the still-undeciphered script — across an extent from Sutkagen-dor to Alamgirpur, the largest Bronze Age civilization by area.
Trade linked the Indus system to Mesopotamia via the Persian Gulf and Lothal's dockyard (Meluhha); decline is now explained by ecological/climatic stress and network breakdown, not an Aryan invasion.
'First urbanization' names Harappa; the syllabus reserves 'Second Urbanization' for the Mahajanapadas of the 6th century BCE — the two frame Unit I from either end.

Practice questions (9)

Attempt each one before opening the answer. Every explanation names the tempting wrong option as well as the right one, because that is where marks are lost.

The study of coins — their metal, weight and legend — as a category of historical source is called:
1. Numismatics
2. Epigraphy
3. Exploration
4. Seriation
Show answer
Answer: A — Numismatics
Numismatics is specifically coin-study; epigraphy studies inscriptions, exploration is site survey without digging, and seriation is a relative dating method using artefact-type sequences.
Radiocarbon (Carbon-14) dating is applied to:
1. Organic remains
2. Burnt clay and pottery only
3. Wood only
4. Stone tools only
Show answer
Answer: A — Organic remains
Carbon-14 dating works on any organic material; thermoluminescence dates fired clay/pottery, and dendrochronology dates wood via tree rings — the three are distinct absolute methods for different materials.
Megasthenes' 'Indica', known through later citations, is an example of:
1. A Greek foreign account
2. An indigenous secular text
3. A Chinese pilgrim account
4. An Arabic geography
Show answer
Answer: A — A Greek foreign account
Megasthenes was a Greek ambassador at the Mauryan court; Fa-Hien, Hiuen Tsang and I-tsing are the Chinese pilgrim-travellers, and Arab geographers form a separate later category.
The earliest known Neolithic settlement in the subcontinent, showing the transition to domestication, is:
1. Mehrgarh
2. Kalibangan
3. Lothal
4. Chanhudaro
Show answer
Answer: A — Mehrgarh
Mehrgarh, in present-day Balochistan, is the earliest and most complete Neolithic sequence in the region; the other three are mature Harappan (urban) sites.
Which of the following are regional Chalcolithic painted-pottery cultures of the Deccan/western India?
1. Ahar-Banas
2. Malwa
3. Jorwe
4. Kot Diji
Show answer
Answer: A — Ahar-Banas; B — Malwa; C — Jorwe
Ahar-Banas, Malwa and Jorwe are Chalcolithic cultures; Kot Diji is an earlier regional culture that fed into the mature Harappan phase, not a Chalcolithic painted-pottery tradition of the Deccan.
The Harappan dockyard associated with maritime trade is located at:
1. Lothal
2. Dholavira
3. Kalibangan
4. Banawali
Show answer
Answer: A — Lothal
Lothal in Gujarat has the well-known dockyard structure; Kalibangan is known for its fire altars and Dholavira for its water-conservation and signboard.
Mesopotamian texts refer to a trading region called 'Meluhha', widely identified with:
1. The Indus region
2. The Gangetic plain
3. The Deccan plateau
4. Sri Lanka
Show answer
Answer: A — The Indus region
Harappan seals found at Ur and Mesopotamian references to Meluhha are the standard evidence cited for Indus-Mesopotamia trade via the Persian Gulf.
The leading current explanation for the decline of the Harappan civilization emphasises:
1. Ecological/climatic stress and breakdown of trade and administrative networks
2. A sudden Aryan invasion destroying the cities
3. Volcanic eruption
4. Conquest by the Mauryan empire
Show answer
Answer: A — Ecological/climatic stress and breakdown of trade and administrative networks
The invasion theory is no longer the accepted account; ecological stress (shifting/drying river systems), climatic change and network breakdown are the current leading explanations.
Name the Harappan site in Rajasthan best known for its distinctive fire altars.
Numerical answer — type the value.
Show answer
Answer: Kalibangan
Kalibangan, on the Ghaggar in Rajasthan, is distinguished by its row of fire altars, read by many scholars as evidence of ritual practice distinct from Mohenjo-daro's Great Bath.