Assertion: Kshatriyas or the kings laid down codes of social behaviour in great detail when new towns started emerging in ancient India.
Reason: The interaction of diverse people in the newly developed towns of ancient India may have sparked inquiries and challenges to the established Brahmanical beliefs and practices.

The Assertion is incorrect but the Reason is correct.

The rise of new towns brought about increased complexity in social life as individuals from different regions gathered to engage in trade, exchange goods, and exchange ideas within the urban setting. This interaction of diverse people may have sparked inquiries and challenges to the established Brahmanical beliefs and practices. In response to these emerging challenges, the Brahmanas took the initiative to formulate comprehensive codes of social conduct. These codes were meticulously designed to be adhered to primarily by the Brahmanas themselves, while also extending their influence to the broader society.