Explanation: Sixth century BCE was a period of intense intellectual ferment. There are several reasons for the emergence of this ferment.

• State formation and the rigidity of the Vedic religion constrained the liberty of thought and action. A revolt against religious practice of following dogmas found its articulation in heterodox sects.
• The emergence of territorial identities accelerated the process of sociopolitical and economic changes.
• The elite class, disillusioned with the system in place, began to move in protest towards the heterodox religions blossoming in Magadha or middle Ganges plains.
• As the Vedic religion was not fully organised, its reach did not permeate into society and hence people did not find it difficult to follow the newly emerging religious sects.

Source: Tamil Nadu NCERT