Millions of Indians are voting on the first big day of the general election pitting the ruling Congress party against the main opposition BJP.
Polling is being held in 91 seats in 14 states, including in the capital Delhi and the key states of Uttar Pradesh, Kerala, Maharashtra and Orissa.
The nine-phase vote began on Monday and will conclude on 12 May. Votes will be counted on 16 May.
More than 814 million Indians are eligible to vote in the polls.
The anti-corruption Aam Aadmi (Common Man’s) Party, which secured a spectacular result in local polls in Delhi last year, offers a challenge to the main parties.
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 the formation of a government.
Election Commission officials say more than 110 million voters are eligible to cast their votes on Thursday and almost a fifth of the parliament’s 543 seats are up for grabs.
Brisk voting is being reported in Delhi, Bihar, Kerala and Uttar Pradesh, reports said.
Among the early voters in Delhi were members of the Gandhi family – Congress party president Sonia, her son and party vice-president Rahul and daughter Priyanka.
The AAP leader Arvind Kejriwal also voted early.
Voters have turned out enthusiastically to cast their ballots in the politically crucial northern state of Uttar Pradesh, which sends the most number of MPs, 80, to parliament.
Some 16 million voters are eligible to cast their ballots in 10 constituencies in the state.
They include the restive Muzaffarnagar constituency, where at least 65 people were killed and 51,000 people – mostly Muslims – were displaced after Hindu-Muslim clashes in September.
The BBC Hindi’s Nitin Srivastava in Muzaffarnagar says a number of displaced people living in camps in the area turned up to vote early on Thursday.
“We want to vote to ensure nothing unfortunate happens to us ever again,” Bano, a 42-year-old camp resident said.
Election officials said by noon, 31% voters had already cast their ballots in Muzaffarnagar.
Early voters
The BBC’s Geeta Pandey in Delhi says voters at a school in the Sarvapriya Vihar district began queuing as polling opened at 07:00 (01:30 GMT).
Soon, several dozen people had queued up to cast their votes and the lines were getting longer by the minute.
There was a big turnout of women in Kerala, which has more female voters than men.
People have told the BBC’s Yogita Limaye in Elamkunnapuzha, just outside the city of Cochin that they want a new government to improve infrastructure in their state, to build better roads and ensure enough water supply.
The marathon vote is being staggered over five weeks for security and logistical reasons.
High security
Thousands of police and paramilitary security personnel have been deployed to ensure polling passes off peacefully.
On Thursday, two soldiers were killed and three others injured in a landmine explosion blamed on Maoist rebels in Jamui, a rebel stronghold in the eastern state of Bihar, police said.
The blast occurred before polling began, but voting has remained unaffected in the area.
On the first day of voting on Monday, polling took place in six constituencies in two states in the north-east – five in Assam and one in Tripura.
In the second phase on Wednesday, voting was held in six seats across four states.
The main contest in the elections is between the Congress, led by Rahul Gandhi, the latest member of India’s influential Nehru-Gandhi dynasty, and the BJP, led by the charismatic and controversial Hindu nationalist leader Narendra Modi.
Mr Modi, who is ahead in all the pre-election opinion polls, is the leader of Gujarat state, which witnessed one of India’s worst anti-Muslim riots in 2002.
The BJP has promised to improve the economy and infrastructure and curb corruption if it wins in the general elections.
The party launched its manifesto hours after polling began for the first phase.
The Congress party has promised “inclusive growth” if it returns to power.
In its election manifesto, the party promised a raft of welfare schemes, including a right to healthcare for all and pensions for the elderly and disabled.
Any party or a coalition needs a minimum of 272 MPs to form a government.
Source: BBC