Caste system among Muslims

Contrary to Qur'anic worldview and Islamic teaching in general, some Muslim communities around the world still apply a system of social stratification that has similarity to the caste systems.
Religious, historical and sociocultural factors have helped define the bounds of endogamous groups for Muslims in South Asia, the Middle East and other parts of world. There is a preference for endogamous marriages based on the clan-oriented nature of the society, which values and actively seeks similarities in social group identity based on several factors, including religious, sectarian, ethnic, and tribal/clan affiliation. This phenomenon however, does not appears in many other muslim regions like in South East Asia. Religious affiliation is itself multilayered and includes religious considerations other than being Muslim, such as sectarian identity (e.g. Shia or Sunni, etc.) and religious orientation within the sect (Ithnā‘ashariyyah, Ismaili). Both ethnic affiliation (e.g. Sindhi, Baloch, Punjabi, etc.) and membership of specific Biraderis (brotherhoods) or Jat/Quoms (see Jātis) are additional integral components of social identity. Within the bounds of endogamy defined by the above parameters, close consanguineous unions are preferred due to a congruence of key features of group- and individual-level background factors as well as affinities.