India, the world's biggest democracy, has set dates for its next general elections, with polling to start on April 7.
Elections to 543 parliamentary seats would be held in nine phases staggered over the months of April and May, the country's election commission announced on Wednesday.
The last phase of polling will be held on May 12, with results expected by May 16.
India holds elections in phases for logistical and security reasons.
Chief Election Commissioner V S Sampath said 814 million people would be eligible to vote - 100 million more than in the last elections in 2009 - a number larger than the population of Europe, making this the biggest election the world has ever seen.
The ruling United Progressive Alliance led by the Congress party is set to face a serious challenge from the opposition Bharatiya Janata Party (BJP) in the elections.
Several opinion polls have placed the BJP and its prime ministerial candidate Narendra Modi as clear frontrunners.
Running on his strong economic track record as chief minister of the state of Gujarat, Modi has emerged as the favourite, reflecting popular anger over corruption and scandals that have plagued the Congress-led federal government.
Exuding self-confidence, Modi has won the support of many middle-class Indians who even a year ago would not have voted for a man accused by critics of failing to stop, or even tacitly encouraging, a spasm of Hindu-Muslim bloodshed in Gujarat in 2002.
Modi has denied any wrongdoing and the Supreme Court has said there is not enough evidence to pursue investigations.
With half of India's population under 25, a record number of first-time voters is expected to participate in the election and
many appear open to Modi's promises of job creation and efficient government.
"I think everyone is looking for strong leadership. This places Modi at an advantage. He's showing that he's a strong
leader," said Mohan Guruswamy of the Centre for Policy Alternatives, a Delhi-based think-tank.
However, India's fragmented political landscape and first-past-the-post system for parliamentary seats makes results
notoriously hard to predict, and that means a victory is by no means assured for Modi's BJP.
Leading the campaign for the Congress party is Rahul Gandhi, the latest in line in the Nehru-Gandhi dynasty that has given India three prime ministers and its most powerful contemporary politician, his mother, Sonia Gandhi.
This time, after two consecutive Congress-led governments headed by Prime Minister Manmohan Singh, India seems unlikely to make another Gandhi a prime minister.
Adding to the uncertainty, a new anti-corruption party has emerged as a serious player. The Aam Aadmi (Common Man) Party is not likely to win many seats, but is setting the agenda for other parties by campaigning against high utility prices and corruption.
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.