A complicated belief system widespread in the Subcontinent, especially among Hindus, that individuals are born into a certain social class, a class that relates not to wealth but to the job or trade of the male members of the family. Strict observance of caste locks individuals and populations into the stratum of society they were born in, and successive governments, particularly in India, have attempted to loosen the rigidities that arise from caste. Outsiders, including tribal people and foreigners, have no caste. Many observant Hindus cannot share food or eat with, or have any kitchen utensil touched by, a low-caste or no-caste person. Elaborate rituals are required to purify or render clean any food or utensil that has been contaminated by contact with someone deemed unclean.