Who were Sudras in Aryan social structure

Sudras were the fourth varna in the Vedic social system, comprising the working class and service providers. However, identifying them specifically as 'Dravidians' reflects a controversial and now-discredited theory that associated varna with racial/ethnic categories. The varna system was a social hierarchy within Aryan society itself, not a separation between Aryans and non-Aryans.