Factors Responsible for the Collapse and Decline of Mature Harappan Civilization by 1800 BCE

Introduction:
The Harappan Civilization, also known as the Indus Valley Civilization, was one of the most advanced civilizations of the ancient world. However, by 1800 BCE, the civilization started to decline and eventually collapsed. Several factors were responsible for the collapse and decline of the mature Harappan Civilization.

Environmental Factors:
1. Climate Change: The Harappan Civilization was heavily dependent on the monsoon rains for agriculture. However, climate change led to a decrease in rainfall, which affected agriculture and led to a decline in food production.
2. Soil Erosion: Deforestation and overgrazing led to soil erosion, which affected agriculture and led to a decline in food production.
3. Floods: The Indus River and its tributaries were prone to floods, which caused destruction of crops, infrastructure, and led to the displacement of people.

Social Factors:
1. Decline in Trade: The Harappan Civilization was known for its trade with other civilizations. However, the decline in trade led to a decline in the economy, which affected the overall social structure of the civilization.
2. Class Conflict: The Harappan Civilization was divided into different social classes. However, class conflict led to a decline in social harmony, which affected the overall stability of the civilization.
3. Disease: The spread of diseases, such as cholera and tuberculosis, led to a decline in the population, which affected the overall social structure of the civilization.

Political Factors:
1. Invasion: The Harappan Civilization was invaded by the Aryans, who were a nomadic tribe from Central Asia. The invasion led to a decline in the political power of the Harappan Civilization.
2. Weak Leadership: The Harappan Civilization had weak leadership, which led to a decline in the political power of the civilization.

Conclusion:
In conclusion, several factors were responsible for the collapse and decline of the mature Harappan Civilization by 1800 BCE. These factors include environmental, social, and political factors, which affected the overall stability of the civilization. The decline of the Harappan Civilization marked the end of one of the most advanced civilizations of the ancient world.

It can be because of 2 factors
1. Natural factors like disasters eg flood, drought etc
2. Anthropogenic factors eg: Aryan invasion theory, war etc.