These are the Dhobis, a Hindu caste, born into the job of doing laundry.

NPR: Mumbai's Dhobi Toil With Laundry

The Chowdulis are Muslim, and therefore outside of the traditional Hindu caste system.

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Their lives continue to be influenced by the ancient Hindu caste system, which assigns each person a place in the social hierarchy.

BBC: India profile

They are reinforced by a Hindu caste-system perhaps even more entrenched than that in India, and by the discrimination long suffered by the Madhesi people of the lowland plains neighbouring India.

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Christian converts, most of whom are born as dalits at the bottom of the Hindu caste system, often hide their new faith for fear of losing their rights to state jobs and university places kept for the lower castes.

ECONOMIST: Religious conversions

Jawaharlal Nehru, India's political leader to independence from British rule in 1947, and its first prime minister, was born into a high-caste Hindu family and became a resolute secularist.

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That would probably make it the second-biggest party in India's most populous state, behind the Samajwadi party, a low-caste Hindu outfit and sometime Congress ally, which was expected to win 23 seats.

ECONOMIST: India's election

The Kumbh Mela brings together Hindus of all castes and creeds, but its most famous attendees are the sadhus (wandering Hindu holy men who have renounced caste, money, possessions and social position).

BBC: India hosts the world��s biggest gathering

By contrast, his friend hailed from a Kurmi agrarian caste that is lower on the Hindu hierarchy.

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