Indians are voting in 124 constituencies taking part in the first round of general elections. The five-phase vote runs until 13 May.
Voters began queuing early at many polling stations. More than 700 million Indians overall are eligible to vote.
Unlike in many Western democracies, the number of Indians voting has increased with every general election. And poorer people are more likely to vote than the rich.
More than two million security personnel have been deployed. Maoist rebels have threatened to disrupt the vote.
A voter uses an Electronic Voting Machine (EVM) at a school building turned polling station in Koderma in Jharkhand state. Electronic vote counting was first used in India during the elections in 2004.
Bharatiya Janata Party (BJP) candidate for Delhi and former minister Vijay Goyal shows a victory sign as he arrives to file his election nomination papers in the capital.
Congress Party candidate Kapil Sibal, current minister for science and technology and ocean development, with his supporters in Delhi.
Two main coalitions are vying for power: the United Progressive Alliance (UPA) and the main opposition National Democratic Alliance (NDA). A "third front" of smaller parties could also play a key role.
Reflecting the diversity of India, tribal women walk out of a polling booth after casting their votes at Rangareddy district on the outskirts of Hyderabad in southern India.
Large scale boundary changes since the last elections contribute to the difficulty of predicting the outcome.
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