Though the Indian caste system is historically linked to Hinduism, it is also followed by Muslims, Sikhs and Christians in the subcontinent[1]. The Indian Constitution has formally outlawed the caste system. The caste system is gradually declining, especially in urban areas and in the public sphere where it is all but nonexistent. However, it is still a major part of Indian societal structure in the private sphere, and caste practices are strongly adhered to in the rural areas.

A varna is a division of the society that consists of many sub-castes or Jātis. Manusmriti and some other shastras mention four varnas: The Brahmins (teachers, scholars and priests), the Kshatriyas (kings and warriors), the Vaishyas (traders, landowners and some artisan groups), and Shudras (agriculturists, service providers, and some artisan groups). Another group of untouchables excluded from the main society was called Parjanya or Antyaja. This group of former "untouchables" (Dalit) was considered either the lower section of Shudras or outside the caste system altogether.

Mixed in with the varna caste system was the jati sub-caste system. The jati was effectively a system similar to guilds, and was associated with occupation. Unlike the varnas, jati could originally be changed with occupation within a varna. According to the Manusmriti, every caste belongs to one of the four varnas. However, there have been many disputes about the varna of many castes, such as castes being considered Kshatriya by some scholars, while described as Shudra by others. While texts such as the Manusmriti attempted to rationalize ambiguous castes by placing them in varna-sankaras (i.e. mixed varna), a more complex system of subcastes and jātis is evident.

In the past some individuals were excommunicated out of the caste (thus becoming an "outcaste") if they committed some unpardonable offences. They were denied the privilege of mingling socially with the rest of their former caste.