For the first time in over 24 years, India's main opposition Congress party will, on Monday, vote to elect a non-Gandhi president.

In the electoral fray are 80-year-old Mallikarjun Kharge, considered close to interim Congress president Sonia Gandhi, and a relatively young Shashi Tharoor, a former UN diplomat.

A total of 9,000 Congress delegates, representing all Indian states and Union territories, are eligible to exercise their franchise in the poll.

"Arrangements have been made for smooth polling," Madhusudan Mistry, head of the Congress' election authority, told the local media on Sunday.

While Kharge is a staunch Gandhi family loyalist with 50 years of political experience, 66-year-old Tharoor is an articulate leader who joined the grand old party in 2009 after nearly a 30-year stint in the UN.

A PhD from the Fletcher School of Law and Diplomacy, Tharoor served as India's junior Foreign Minister when the Congress was in power from 2004-2014.

The results of the Congress presidential poll will be out on October 19.

Since Prime Minister Narendra Modi's nationalist BJP swept to power in 2014, the Congress has witnessed a vertiginous decline. The Congress is now in power only in a handful of Indian states.

Often blamed for the party's poor performance, Sonia's son Rahul Gandhi has refused to take over the reins of the party in the run-up to the general elections slated for 2024.