Archaeological Evidence of Decline of Indus Valley Civilization

Key cities like Harappa, Mohenjodaro, and Kalibangan demonstrated a gradual decline in urban planning and construction.

• Houses were built using old, deteriorating bricks, and encroachments began to obstruct roads and streets.
• Once-thriving urban centers transformed into slums.
• Entry points to significant structures like the Great Bath and Granary were blocked, rendering them unusable over time.
• In later stages of Mohenjodaro, there was a noticeable reduction in sculptures, figurines, beads, bangles, and inlay works.
  • The city of Mohenjodaro, which originally spanned 85 hectares, eventually shrank to a mere 3 hectares.
• Similar signs of decline were observed in Kalibangan and Chanhudaro, where structures associated with power and prestige deteriorated, and luxury goods became scarce.
• Settlements in the core regions of the Harappan civilization began to dwindle, leading to depopulation or migration to other areas.
  • The number of sites in the Harappa-Bahawalpur-Mohenjodaro triangle decreased, while settlements in Gujarat, East Punjab, Haryana, and the Upper Doab saw an increase.
• Hallmarks of the civilization, such as writing, uniform weights, pottery styles, and architectural techniques, disappeared.
• The cities of the Indus Valley were largely abandoned around 1800 BCE, a date corroborated by Mesopotamian texts, which ceased references to Meluhha by 1900 BCE.

Theories of Abrupt Decline of Indus Valley Civilization

• Floods and Earthquakes (R.L. Raikes Hypothesis)

• • Renowned hydrologist R.L. Raikes attributed the decline to catastrophic flooding that caused prolonged submergence of cities near the Indus River.

• Mohenjodaro’s houses and streets were often buried under layers of silty clay and collapsed materials, believed to be remnants of floodwaters.
• The inhabitants rebuilt structures atop the debris left by receding floods.

• Violent earthquakes, river damming, and widespread destruction of towns disrupted the Harappan economy, which relied heavily on riverine and coastal trade.

• Shifting of the Indus River (H.T. Lambrick)

• • Scholar H.T. Lambrick rejected the catastrophic flooding theory and suggested that changes in the Indus River’s course contributed to the decline.

• The river, being unstable, shifted approximately 30 miles away from Mohenjodaro.
• This left the city and surrounding agricultural villages without water, leading to abandonment.

• Lambrick argued that the silt found in Mohenjodaro was a result of wind action and disintegrating brick structures, not floods.
• Critics of this theory questioned why the inhabitants did not establish new settlements if they were accustomed to such riverine changes.

• Increased Aridity and Drying of the Ghaggar-Hakra River (D.P. Aggarwal and Sood)

• • D.P. Aggarwal and Sood proposed that increased aridity and the drying up of the Ghaggar-Hakra River led to the decline.

• Even slight reductions in water availability in semi-arid regions could disrupt agriculture and economy.
• The Ghaggar River, once a major water source, dried up due to tectonic shifts that diverted its tributaries. The Sutlej River was captured by the Indus, while the Yamuna shifted eastward to join the Ganges.

• This loss of water caused catastrophic impacts on towns in the region, leading to the collapse of drainage systems and eventual abandonment.

• Barbarian Invasions (Mortimer Wheeler)

• • Archaeologist Mortimer Wheeler argued that Aryan invasions were responsible for the decline of the Indus Valley Civilization.
  • Late-phase skeletons found in Mohenjodaro’s streets suggest a violent end.
  • The Rig Veda refers to the destruction of fortresses by Aryans, with Indra (referred to as Purandara, destroyer of forts) playing a key role.
  • Wheeler believed Harappan cities were described in the Rig Veda, with references to a battle at Hariyupiya, located near the Ravi River.
  • However, this theory has been widely criticized:
  • The decline of the Harappan civilization occurred around 1800 BCE, while Aryans are believed to have arrived around 1500 BCE.
  • No conclusive evidence of military assault has been found in Harappa or Mohenjodaro.

Theory of Gradual Decline of Indus Valley Civilization

• Ecological Imbalance (Walter Fairservis)

• • Walter Fairservis attributed the decline to ecological imbalances in semi-arid regions.
  • Overpopulation of humans and cattle depleted limited forest resources, food, and fuel.
  • The combined demands of townspeople, peasants, and pastoralists exceeded the region’s production capacity.
  • Deforestation and loss of grass cover increased instances of floods and droughts.
  • This environmental strain caused economic collapse, prompting gradual migration to more fertile areas.
  • Harappan communities moved toward Gujarat and eastern regions, abandoning the Indus heartland.
  • Fairservis’s ecological theory is considered one of the most plausible explanations for the gradual decline of the Indus Valley Civilization.

Survival of the Indus Valley Civilization

• The Indus Valley Civilization’s decline did not mark the end of its traditions. Archaeological evidence suggests that Harappan communities merged into surrounding agricultural groups, retaining many traditions. 
• The late Harappan phase is classified into distinct geographical zones. 

Geographical Zones of Indus Valley Civilization

• Sindh:
  • Represented by Jhukar culture at Chanhudaro and Amri.
  • Gradual changes observed in seals, cubical weights, and writing, which was limited to pottery.
  • Introduction of Jhukar pottery, a buff ware with red slip and black-colored paintings.
  • Distinctive metal objects suggest trade links with Iran.
• Punjab, Haryana, and Rajasthan:
  • Sites like Mitathal, Bara, Ropar, and Siswal remained active.
  • Decline of Harappan pottery; regional pottery traditions emerged.
  • Cemetery-H culture in Punjab and Ghaggar-Hakra valley linked to Harappan traditions.
  • Evidence of brick houses in Bara and Siswal.
• Ganga-Yamuna Doab:
  • Smaller settlements with daub and wattle houses.
  • Focus on agriculture as a primary livelihood.
• Kutch and Saurashtra:
  • Urban decline evident in Rangapur and Somnath.
  • Rangapur introduced Lustrous Red Ware pottery.
  • Shift from Indus weights and tools to locally sourced stone tools.
  • Increased number of settlements during the late Harappan stage (~2100 BCE).

Survival of Harappan Civilization

Priestly traditions may have merged with Aryan ruling groups.

• Continuity in religious practices, such as Pasupati (Siva), mother goddess worship, and phallic symbols.
• Sacred rivers, trees, and animals trace their origins to Harappan traditions.
• Evidence of fire worship and sacrifice at Kalibangan and Lothal.
• Domestic practices like house plans and water management persisted.
• Traditional weight systems based on a ratio of sixteen originated from the Harappans.
• Craftsmanship in pottery and tools continued, evident in modern techniques.
• Bullock carts and boats used today have roots in Harappan cities.