The decline of the Indus Valley civilization likely resulted from environmental degradation, changes in the river and monsoon patterns, disease, and possibly external invasions. A lack of a centralized authority may have made recovery from these issues more challenging, leading to the civilization's collapse around 1500 BCE.
Theories on the Decline of the Indus Valley Civilization:
- Experts have proposed several theories regarding the disappearance of the Indus valley cities. Environmental degradation, from extensive use of resources, and a high population density are considered significant factors that contributed to the decline.
- This situation might have been exacerbated by climate change leading to a dramatic shift in the Indus River floodplain and changes in monsoon patterns, which would have disrupted the water supply essential for irrigation and drinking.
- Tectonic activity is another hypothesis that suggests changes in river courses, which could have impacted the civilization's agricultural foundations. Disease epidemics are also potential causes that could have decimated the population.
- The Indus valley might have been more vulnerable to these environmental challenges due to a lack of a powerful centralized state, which led to difficulties in managing the complex societal needs.
In addition to environmental factors, there is a theory that the Indus valley civilization fell prey to conquests by the Aryans, nomadic Indo-European pastoralists. However, this theory has been revisited in light of new evidence emphasizing environmental and internal societal factors over external invasion.
Ultimately, by around 1500 BCE, the sophisticated social and political systems of the Indus valley had disintegrated, leading to the abandonment of their distinct urban planning, writing system, and artisanal crafts. This marks the end of a civilization that significantly influenced the later cultures of the region.