India, your move now. 10-point cheatsheet on elections.

Voting will be held over nine days starting April 7 and ending May 12.

Chief Election Commissioner VS Sampath said 814 million people will be eligible to vote, 100 million more than in the last elections in 2009.

The number of voters is larger than the population of Europe, making this the biggest election the world has ever seen.

With half of India's population under 25, a record number of first-time voters is expected to participate in the election.

The opposition Bharatiya Janata Party, led by Narendra Modi, has the momentum heading into the elections. Recent polls show the BJP well short of a majority of the 543 Lok Sabha seats at stake, but widening its lead over the ruling Congress, which has ruled for more than two-thirds of the 67 years since independence but may now be headed for its worst-ever electoral defeat.

Rahul Gandhi is leading the Congress' campaign. The party has been pummelled by corruption scandals, relentless inflation and an inert economy.

A multi-headed "Third Front" including the Left and various regional powerhouses like Mulayam Singh Yadav's Samajwadi Party is also eyeing power, a reflection of the growing clout of state-based leaders.

New to the mix is also Arvind Kejriwal's anti-corruption Aam Aadmi Party. Analysts say while it is not likely to win many seats, it is setting the agenda for other parties by focusing on malversation and crony capitalism.

The election comes as the economy is on course to grow at below five percent for the second year running, which would be the worst performance since the 1980s for a country that a few years ago was confident of matching China's run of double-digit expansion.

As the election drumbeats get louder, overseas investors have extended a buying streak of shares, totalling $800 million in a run of 13 sessions until Tuesday. Businesses have put investment plans on hold ahead of the elections, leading to a contraction in capital formation and worsening a slowdown that could, however, be reversed after results are declared in May.