Indians have begun voting in the world’s biggest election, with the ruling Congress party pitted against the Hindu nationalist BJP opposition.

The nine-phase ballot begins on Monday and concludes on May 12. Votes will be counted on May 16.

More than 800 million Indians are eligible to vote in a poll dominated by corruption and high inflation.

A new anti-corruption party, the AAP, is also contesting the elections after a spectacular result in local polls.

The AAP (Aam Aadmi, or Common Man’s Party) made a strong showing at the state assembly polls in the capital, Delhi, and is standing for all the seats in the parliament.

Several smaller regional parties are also in the fray and if no single party wins a clear majority, they could play a crucial role in government formation.

The Lok Sabha (lower house of parliament) has 543 elected seats and any party or a coalition needs a minimum of 272 MPs to form a government.

Prime Minister Manmohan Singh has already said he is stepping down and the Congress is being led by Rahul Gandhi, the latest member of India’s influential Nehru-Gandhi dynasty.

The BJP is being led by the charismatic and controversial Hindu nationalist leader Narendra Modi. Mr Modi, who is ahead in all the pre-election surveys, is the leader of Gujarat state, which witnessed one of India’s worst anti-Muslim riots in 2002.