Ritual pollution is a condition of major concern in certain cultures, possibly under the influence of particular religions, such as Islam and Judaism. It is a determining factor in the reinforcement of the caste system in India.
The concept of ritual pollution is a powerful and enduring social control mechanism in Indian society; concepts of purity, pollution, and defilement are a reflection of cultural attitudes to the body and the organisation of these attitudes into a status hierarchy.
It's to treat people socially as if they are contaminated (segregation). Sources suggest that when the US had a Caste System, they practiced ritual pollution.
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