Caste is a form of social stratification characterized by endogamy, hereditary transmission of a style of life which often includes an occupation, ritual status in a hierarchy, and customary social interaction and exclusion based on cultural notions of purity and pollution. Its paradigmatic ethnographic example is the division of India's Hindu society into rigid social groups, with roots in India's ancient history and persisting to the present time. However, the economic significance of the caste system in India has been declining as a result of urbanization and affirmative action programs. A subject of much scholarship by sociologists and anthropologists, the Hindu caste system is sometimes used as an analogical basis for the study of caste-like social divisions existing outside Hinduism and India. The term "caste" is also applied to morphological groupings in female populations of ants and bees.
