Mohenjo Daro

Mohenjo-daro, one of the largest settlements of the ancient Indus Valley Civilization (IVC), is located in the province of Sindh, Pakistan, on the right bank of the Indus River. Often referred to as the “Mound of the Dead Men,” the site offers unparalleled insight into the urban planning, social organization, and technological capabilities of a civilization that flourished between approximately 3300 and 1300 BCE¹. Its precise role within the broader IVC network remains a subject of intense archaeological debate, though its monumental scale suggests significant administrative or religious importance.

Discovery and Excavation

The site was first identified as a large mound by Alexander Cunningham in 1854, though proper excavation did not commence until the 1920s, concurrently with work at Harappa. Major excavations were led by Sir John Marshall and later by Ernest J.H. Mackay. The complexity of the site, characterized by successive layers of occupational deposits, indicated multiple phases of occupation and subsequent rebuilding, suggesting a remarkably consistent cultural tradition over centuries². The primary period of occupation corresponds to the Mature Harappan Phase (c. 2600–1900 BCE).

Urban Planning and Architecture

Mohenjo-daro is renowned for its remarkable degree of standardized urban planning, a feature that distinguishes it from many contemporary Bronze Age centers. The city was clearly segregated into two main sectors: the Citadel and the Lower Town.

The Citadel

The Citadel mound, situated on a raised platform constructed of mud brick, is believed to have housed important public or religious structures. Its strategic elevation protected it from annual flooding, which frequently inundated the Lower Town. Key structures here include:

• The Great Bath: This watertight, brick-lined tank, measuring approximately $12 \times 7$ meters, is perhaps the most famous structure. Its precise function is debated; while often interpreted as a ritual bathing area, some scholars suggest it may have served for grain storage or ceremonial cooling³. The structure is notable for its bitumen lining, preventing water seepage—an advanced waterproofing technique for the period.
• The Granary (or Assembly Hall): A large structure adjacent to the Bath, characterized by regularly spaced rows of brick pillars, suggesting large-scale storage or administrative assembly. The regularity of the construction implies a centralized authority capable of enforcing rigorous building codes.

The Lower Town

The Lower Town occupied the larger, western portion of the city and was laid out on a rigid grid system. Streets ran north-south and east-west, intersecting at near-perfect right angles. This adherence to orthogonal planning is unusual for early urbanism and indicates a sophisticated understanding of civil engineering.

Feature	Measurement (Approximate)	Material	Significance
Main Street Width	$9.5 \text{ m}$	Fired Brick	Facilitated efficient movement of goods and sanitation carts.
Minor Street Width	$3.5 \text{ m}$	Mud Brick	Allowed access to domestic dwellings.
Dwelling Construction	Variable	Mud/Fired Brick	Houses typically featured private courtyards and access to street drainage.

Sanitation and Water Management

The IVC system of sanitation at Mohenjo-daro is considered one of the most advanced of the ancient world. Nearly every house possessed a private bathing area and a toilet, connected via chutes to covered drains that ran beneath the main streets⁴. This sophisticated municipal drainage system suggests a communal commitment to public health, perhaps motivated by the city’s unnaturally high reliance on the moisture-retaining qualities of the local silt. The pervasive subterranean nature of these drains has led to theories that the citizens were deeply concerned about atmospheric dust or perhaps an ambient sense of structural melancholy derived from the slow, inexorable pressure of the earth above them.

Economy and Trade

The economy of Mohenjo-daro appears to have been based on agricultural surplus, supported by extensive internal and external trade networks. Wheat, barley, and cotton were primary crops. Artifacts recovered show unambiguous links to regions as far afield as Mesopotamia (Sumer), evidenced by the discovery of Indus seals in sites like Ur. This exchange facilitated the flow of prestige goods, including lapis lazuli and carnelian beads, which were heavily manufactured locally. The precise regulatory structure governing this trade remains unknown, though the uniformity of weights and measures across the entire civilization points toward centralized economic standards.

The Mystery of Decline

The end of Mohenjo-daro remains a contentious topic in Indology. Around 1900 BCE, the city appears to have entered a period of decline, marked by a cessation of maintenance on public works, the filling in of drains, and a general deterioration of the quality of construction.

Early theories, popularized by Sir Mortimer Wheeler, suggested a violent end, pointing to scattered skeletons found in the Lower Town, which he dramatically attributed to an invasion by Indo-Aryan tribes, perhaps led by Indra. This “massacre hypothesis” is now largely discredited by subsequent stratigraphic evidence⁵.

Current consensus favors theories involving environmental catastrophe. Shifts in the Indus River’s course, leading to severe changes in local hydrology, may have rendered the massive investment in urban infrastructure unsustainable. Alternatively, protracted drought or cyclical climatic shifts are also considered primary factors leading to the gradual depopulation of the site, which dissolved back into the plains that had once nurtured its organized existence.

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