Reasons of Decline of Ancient Harappan Civilization3
Continued from part 2
The later layers of the buildings at Harappa and Mohenjo-daro as well as at other sites also showed a clear deterioration in the quality of construction and building materials. There were also a few smashed skulls. But these have been dated somewhat earlier than the period when the civilization disappeared from history.
There was a marked decline in the quality of building and town planning. This indicated that the priestly elite were losing control. Some of the migrants probably were bands of Aryan herders. These herders entered the Indus region over an extended period of time, rather than in militant waves. But the Aryan pastoralists may have consciously destroyed or neglected the dikes and canals on which the agrarian life of the Harappan peoples depended.
Extensive cattle rising subsequently replaced intensive crop cultivation. This further undermined the economic basis of the civilization. That there was a good deal of violent conflict in this transition cannot be ruled out. Groups of skeletons in postures of flight have been found on the stairways at some sites.
There is evidence of burned-out settlements and the flight of refugees. These exist through the passes into the Himalayas to the north. Thus, a combination of factors brought an end to India's first civilization. These factors also gave rise to an extended transition period, dominated increasingly by the nomadic Aryan invaders.
Thus, it is likely that a combination of factors led to Harappa's demise. There is also evidence of severe flooding at Mohenjodaro and other sites. Short-term natural disasters may have compounded the adverse effects of long-term climatic changes.
Shifts in the monsoon pattern and changes in temperature may have begun the process of desertification. This eventually transformed the region into the arid steppe that it has remained for most of recorded history. There have also been rapid changes in types of pottery. These suggest a series of sudden waves of migrants into the region. It is possible that the Harappans were too weak militarily to prevent these incoming peoples from settling in or taking over their towns and cities.
Also the Indus Valley civilization flourished between the time period from 3300 to 1700 BCE. It was started around 1900BCE that it began to decline. This resulted as people started leaving and the cities started to becoming deserts devoid of population.
There are many reasons attributed for this decline. One of these theories included the tectonic activity along the Indo-Asian plate boundary, or flooding. Another reason could be the disappearance of the Ghaggar-Hakra river system. This river system was a part of Sarasvathi. Then there is the infamous Aryan invasion theory.
The latest research so conducted held that it was not Aryans, but monsoons, which were responsible for the demise of the Indus Valley Civilization. Due to the effect of monsoons over the past 10,000 years, it has been infered that a strong monsoon helped the civilization to grow. Similarly, scanty monsoon might have also led to its decline.
According to the Arabian Sea sediments and other geological studies, the monsoon began to weaken about 5,000 years ago. The dry spell lasted several hundred years. These could have even led people to abandon the Indus cities and move eastward into the Gangetic plain. This was because this area received higher rainfall than the northwestern part of the subcontinent.
About 1,700 years ago, the monsoon began to improve again. This led to an increased farm produce for several centuries. Eventually, this also contributed to the relative prosperity in India during the medieval ages. This took place from 700 to 1200AD respectively.