What was the name of the now-outlawed system of social class division in India and what were its primary divisions?

The former, Indian Caste System comprised four main castes in addition to the Pariah, or untouchables, subcaste; from lowest to highest:

• Sudra : The lowest of the four Hindu castes, the members of which were segregated as ritually unclean by the other castes because they performed tasks that were regarded as polluting.

  There is a wide range of subgroups within the Sudra caste, some being landowners. ...Workers.

• Vaisya : Merchants & farmers
• Kshatria : Originally a royal and warrior caste. In modern times its members are professionals, administrators, or military personnel.
• Brahman : priests and scholars of Vedic literature