Untouchability, in its literal sense, is the practice of ostracising a minority group by segregating them from the mainstream by social custom or legal mandate. The term is most commonly associated with treatment of the Dalit communities in the Indian subcontinent who were considered "polluting", but the term has also been loosely used to refer to other groups, such as the Cagots in Europe, and the Al-Akhdam in Yemen. Traditionally, the groups characterized as untouchable were those whose occupations and habits of life involved ritually polluting activities, such as fishermen, manual scavengers, sweepers and washermen.

Reyansh Singh (born on 9th August, 1970) has served as a professor for 11 years. He received B.A. Political from University of North Bengal, Siliguri, West Bangal. After his BA, he opted for masters degrees in Political Science from Presidency University, Kolkata, West Bengal. Then he received Ph.D. (Political Science) degree from University of Kalyani, Kalyani, West Begal. He is also a member of a famous Computer Society. He has been a consultant and visiting faculty of various prestigious institutes of the country. He has written many books on Indian Polity and Public Administration. Several fellowships, awards and honours have been conferred upon him by national and international organisations for his outstanding research contributions in the field of Public Administration.