The notions of purity and pollution are critical for defining and understanding caste hierarchy. According to these concepts, Brahmins hold the highest rank and Shudras the lowest in the caste hierarchy. The Varna System represents a social stratification which includes four varnas namely- Brahmans, Kshatriyas, Vaisyas and Shudras.The Shudras were allocated the lowest rank of social ladder and their responsibilities included service of the three Varnas. The superior castes tried to maintain their ceremonial purity
Dumont holds the notion of purity and pollution interlinked with the caste system and untouchability.The hierarchy of caste is decided according to the degree of purity and pollution. It plays a very crucial role in maintaining the required distance between different castes. But the pollution distance varies from caste to caste and from place to place.
Dipankar Gupta observes that the notion of purity and pollution as Dumont observed is integrally linked with the institution of untouchability .But unlike untouchability the notion of purity and pollution is also a historical accretion. Over time this notion freed itself from its specific and original task of separating untouchables from the others and began to be operative at different planes of the caste system.
The concept of purity and pollution plays a very crucial role in maintaining the required distance between different castes. But the pollution distance varies from caste to caste and from place to place.