Outgoing President Abdul Kalam, 75, a physicist and engineer who played a significant role in the country's nuclear program, will cede power on July 24.
In India, the president is the formal head of state. However, executive power is held by the prime minister, and the president's role is largely ceremonial.
The rivalry for the presidential post will be between candidates from India's two leading political forces, the ruling United Progressive Alliance (UPA) and the National Democratic Alliance (NDA), a coalition of opposition forces.
The two blocs are holding active consultations with the largest independent and regional parties, in a bid to win their support.
Although neither party has yet announced its candidates, Minister of Home Affairs Shivraj Patil is considered the most likely candidate from the ruling coalition.
Pranab Mukherjee, the minister of external affairs, is also a possibility, but may opt to continue his role in the government. The opposition is currently considering the candidacy of Vice President Bhairon Singh Shekhawat.
The president in India is elected by members of the Election Board, which includes members of parliament and the legislatures of all Indian states, for a five-year term.
