Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The Election Commission of India held indirect seventh presidential elections of India on 6 August 1977. Even though 37 candidates filed their nominations, 36 of them were rejected, leading to Neelam Sanjiva Reddy being one of the two Presidents of India winning unopposed.
Background
After the death of the sitting president, Fakhruddin Ali Ahmed, on 11 February 1977, the vice-president B. D. Jatti took charge as acting President. An election to the office of President was required to be held within 6 months of the date of the vacancy.
The Electoral College consisted of the members of Lok Sabha (524), Rajya Sabha (232) and 22 state Legislative Assemblies (3776), all together totalling 4532 electors.