Proportional representation by a single transferable vote: the electoral college that chooses the President of India
Background
The President of India is elected by an electoral college made up of the elected members of both Houses of Parliament and the elected members of the Legislative Assemblies of all the States, together with the Legislative Assemblies of the National Capital Territory of Delhi and the Union Territory of Puducherry. Nominated members of Parliament or of State Legislative Assemblies, and members of Legislative Councils, are not electors. Article 55(3) of the Constitution provides that the election shall be held in accordance with the system of proportional representation by means of the single transferable vote, and that the voting shall be by secret ballot. An elector marks preferences against the names of candidates in figures only; the first preference is compulsory for the ballot to be valid, while further preferences are optional. A candidate is declared elected on securing the quota, and political parties cannot issue a whip for this vote.
In plain words
Single transferable vote Single transferable vote — A system in which an elector ranks candidates in order of preference and surplus or lowest votes are transferred to later preferences.