The caste system is a system of social stratification and social restriction.
Caste is neither unique to Hindu religion nor to India; caste systems have been observed in other parts of the world, for example, in Muslim community of Yemen, Christian colonies of Spain, and Buddhist community of Japan, says Wikipedia.
Since 1950 the Indian government officially recognizes historically discriminated lowest castes of India such as Shudras and Untouchables as Scheduled Castes.[9][22] These Schedules Castes are sometimes referred to as Dalit in contemporary literature. In 2001, the proportion of Dalit population was 16.2 percent of India's total population.
Caste, claimed Gandhi, had nothing to do with religion. The discrimination and trauma of castes is the result of custom, whose origin is unknown, and whose origin one does not need to know to spiritually sense that this custom was wrong, that any caste system is harmful to the spiritual well being of man and economic well being of a nation.