The largest democracy in the world is wrapping up its national election.
India's more than 814 million registered voters have been voting in phases for more than a month.
Monday is the final day of polling and results from the almost one million polling stations are expected Friday.
All 543 seats in the lower house of parliament are being contested.
The opposition Bharatiya Janata Party, or BJP, is looking to oust the ruling Congress party, promising to revitalize a stagnant economy.
Outgoing Prime Minister Manmohan Singh has said it would be a disaster if the BJP's Narendra Modi becomes the new prime minister.
Controversy has swirled around the BJP prime ministerial candidate since 2002, when Hindu-Muslim rioting in Gujarat state, which he led, killed more than 1,000 people. India's Supreme Court cleared Modi of charges that he incited the violence.
The controversy appears to have faded for many voters, and Modi has since cast himself as an able administrator and decisive leader who has energized the economy of Gujarat and holds the promise of doing the same for the rest of the country.
Political analysts say the BJP and a new party called the Aam Aadmi Party have used social media more aggressively than the ruling Congress Party whose two top leaders -- Sonia Gandhi and Rahul Gandhi -- have stayed away from online platforms.