The Caste System
In ancient India there developed a social system in which people were divided into separate close communities. These communities are known in English as caste.
The origin of the caste system is in Hinduism, but it affected the whole Indian society. The caste system in the religious form is basically a simple division of society in which there are four castes arranged in a hierarchy and below them the outcast. But socially the caste system was more complicated, with much more castes and sub-castes and other divisions. Legally the government disallows the practice of caste system but has a policy of affirmative discrimination of the backward classes.
http://adaniel.tripod.com/castes.htm
The fact that the 3500-year-old caste system should survive in India today almost defies comprehension. It has been an aberration of the Hindu psyche. Indians who use lofty rhetoric about progress, characterizing their society as "united in diversity," seem to be simply perpetuating the system of social gradation that has blighted so many lives.
http://gbgm-umc.org/nwo/99ja/india.html