"Vote to uphold constitutional values of our republic", - Sitaram Yechury (Secretary General of the Communist Party of India).
Both Kovind and Kumar are Dalits, meaning whoever wins, India is getting a Dalit President.
Addressing a meeting of National Democratic Alliance (NDA) parliamentarians on the eve of the commencement of the monsoon session of parliament, Modi urged the alliance lawmakers, including legislators in the states, to cast their ballot.
During his meeting with BJD legislators, which lasted about an hour, the leaders apprised Kovind of the various issues concerning the state.
Tamil Nadu Chief Minister K. Palaniswami was among the first voters at the assembly complex in Chennai.
The voting began at 10 AM at Tilak Hall in the Assembly complex and ended at 5 PM with 402 out of total 403 MLAs and three MPs casting their votes, ACEO Amrita Soni told PTI.
Presidential Elections 2017: Special pens with violet ink for MPs, MLAs to cast votes
While the presidential poll is being seen as a contest between two Dalit leaders, Kumar had, at a conference earlier this month, described it as a "battle of ideologies". The voting process started at 10 am amid tight security.
The counting of votes will take place on 20 July in New Delhi where all the ballot boxes will be brought from various state capitals.
The results of the poll would be announced on Thursday, five days before Mukherjee's term expires. Former Rajya Sabha member Ramnath Kovind is the NDA's candidate and opposition's candidate for the post of President is former Lok Sabha Speaker Meira Kumar.
The candidate who secures at least one vote more than 50 per cent of the total votes will enter into the Majestic Rashtrapati Bhavan.
The victor of Monday's contest will be India's second president belonging to the Dalit community, after KR Narayanan, who was president between 1997-2002. K.R. Narayanan was the first from the community to hold the post.