The Caste System is part and parcel of the Hindu society. It has been coming through the ages.
Untouchability in India:
A Modern Manu(The Constitution):
There are many laws and rules that have been put forward by the Indian Constitution like,Article 15, which prohibits discrimination, also contains a clause allowing the union and state governments to make “any special provision for the advancement of any socially and educationally backward classes of citizens or for the Scheduled Castes and Scheduled Tribes.” This language was added in 1951 within weeks of a Supreme Court decision outlawing quotas in school admissions. The speed of the amendment is indicative of the strong political support for reservations, Nehru’s personal views notwithstanding. Similarly, Article 16, calling for “equality of opportunity in matters of public employment,” contains clauses permitting the “reservation of appointments or posts in favour of any backward class of citizens which, in the opinion of the State, is not adequately represented in the services under the State” and another allowing “reservation in matters of promotion” for Scheduled Castes and Scheduled Tribes.