B.R. Ambedkar, a towering figure in Indian social thought and a fierce critic of the caste system, identified its features not merely as a system of stratification but as a deeply oppressive and dehumanizing institution. For Ambedkar, the core features of caste were:

1. Hierarchy and Graded Inequality: Unlike a simple division of labor, caste is a division of laborers, where each caste is placed in a graded hierarchy, with Brahmins at the top and Dalits (Untouchables) at the bottom. This hierarchy is not just social but also ritualistic, economic, and political, leading to inherent inequality.
2. Endogamy (Caste as a Closed System): Ambedkar argued that the most crucial feature of caste is endogamy – the prohibition of intermarriage between different castes. This practice, enforced through severe social sanctions, maintains the purity and distinctiveness of each caste, preventing social mobility and integration. He famously stated that 'the superimposition of endogamy on exogamy' is the essence of caste.
3. Hereditary Occupation: Caste dictates one's occupation by birth, limiting individual choice and perpetuating economic disparities across generations. This often led to the stigmatization of certain occupations, particularly those deemed 'unclean' and assigned to lower castes.
4. Purity and Pollution: The concept of ritual purity and pollution is central to the caste system, with higher castes considered pure and lower castes, especially Dalits, deemed impure or 'untouchable.' This ideology justified social exclusion, segregation, and discrimination.
5. Lack of Social Mobility: The caste system is characterized by its rigidity, offering little to no scope for individuals to move up or down the social ladder based on merit or effort. One's status is ascribed at birth.

Difference from Mainstream Treatment:

Ambedkar's understanding differed significantly from the mainstream (often Brahmanical or functionalist) treatment of caste in several ways:

• Emphasis on Oppression vs. Functionalism: Mainstream views, particularly those influenced by early anthropologists or traditional Hindu texts, often described caste as a functional system of division of labor, contributing to social stability. Ambedkar, however, vehemently rejected this, highlighting caste as a system of inherent oppression, exploitation, and denial of human dignity, particularly for Dalits. He saw it as a source of perpetual conflict and injustice, not harmony.
• Focus on Endogamy as Core: While mainstream accounts might list endogamy as a feature, Ambedkar elevated it to the defining characteristic that maintains the system's closed nature and hierarchy. He argued that the prohibition of inter-caste marriage is what truly perpetuates the system.
• Critique of Hindu Scriptures: Unlike those who sought to rationalize caste within a religious framework, Ambedkar directly challenged the religious legitimacy of caste, arguing that it was sanctioned by Hindu scriptures and therefore inherently unjust. He saw Hinduism itself as the source of caste oppression, leading to his eventual conversion to Buddhism.
• Advocacy for Annihilation: Mainstream approaches often focused on reforming caste or mitigating its harsher aspects. Ambedkar, however, called for the 'annihilation of caste' itself, believing that mere reforms were insufficient. He advocated for radical social transformation, including inter-caste marriage and dining, and a complete rejection of the religious basis of caste, to achieve true equality and liberty.

In essence, Ambedkar's analysis was a radical, emancipatory critique, viewing caste through the lens of those who suffered its worst consequences, rather than from the perspective of its beneficiaries or as a neutral social structure.