India has entered the final phase of its marathon election, with 107 million voters eligible to cast ballots.
Voting is in 86 constituencies across nine states and territories, including Tamil Nadu in the south and most parts of the city of Calcutta.
The main fight is between the ruling Congress party-led alliance and parties led by the BJP, although there is a host of regional opposition.
Results are announced on Saturday and an outright majority is unlikely.
A series of exit polls is expected after polling closes at 1700 local time (1130 GMT).
Calcutta violence
The BBC's Sanjoy Majumder in Delhi says that the final phase could well prove decisive as the swing state of Tamil Nadu, with nearly 40 parliamentary seats, has heavily influenced federal politics in the past few elections.
Voters in the states of Punjab, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Uttar Pradesh and West Bengal are also casting ballots on Wednesday, the final day of voting.
Polls are also being held in the federally-administered territories of Chandigarh and Pondicherry.
The BBC's Subir Bhaumik in Calcutta says there have been election clashes in seven places in and around the city, with one person reported dead and 17 injured. There were similar clashes there in last week's voting phase.
All 39 constituencies in the southern state of Tamil Nadu are voting.
Tamil Nadu - where voters tend to hand big victories to one or other of the state's two main parties - is expected to play a crucial role in the formation of the government in the coalition talks that are almost certain to follow the election.
The last five governments have been formed with the winners in Tamil Nadu.
Former state chief minister, J Jayalalitha, head of the AIADMK party and one of India's most colourful and controversial politicians, has cast her vote in the state capital Madras (Chennai) and complained of election irregularities.
She said some election machines were not working properly and in some places paramilitaries were nowhere to be seen.
In Jammu and Kashmir, some separatist groups have called for a boycott of the elections and there has been a two-day strike in the Muslim-majority Kashmir valley.
A former separatist and head of a faction of the regional People's Conference party, Sajjad Lone, has broken ranks to stand for election from Baramullah.
The BBC's Altaf Hussain in Srinagar says turnout in the region is so far very low.
A large number of police and paramilitary troops have been deployed in the capital, Srinagar, to prevent anti-election demonstrations, our correspondent says.
Among the other candidates facing the electorate on Wednesday are Varun Gandhi and Mohammad Azharrudin.
Mr Gandhi, who has been accused of making a controversial anti-Muslim speech, is standing for the Bharatiya Janata Party in Pilibhit in Uttar Pradesh.
Ex-cricketer Azharruddin stands for Congress in Moradabad in the same state.
The first round of the general election on 16 April was marred by Maoist attacks in eastern and central India which killed at least 17 people. Later rounds were less violent.
About two million security personnel are being deployed for the five-phase vote.
The new parliament has to be constituted by 2 June.
Voting is in 86 constituencies across nine states and territories, including Tamil Nadu in the south and most parts of the city of Calcutta.
The main fight is between the ruling Congress party-led alliance and parties led by the BJP, although there is a host of regional opposition.
Results are announced on Saturday and an outright majority is unlikely.
A series of exit polls is expected after polling closes at 1700 local time (1130 GMT).
Calcutta violence
The BBC's Sanjoy Majumder in Delhi says that the final phase could well prove decisive as the swing state of Tamil Nadu, with nearly 40 parliamentary seats, has heavily influenced federal politics in the past few elections.
Voters in the states of Punjab, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Uttar Pradesh and West Bengal are also casting ballots on Wednesday, the final day of voting.
Polls are also being held in the federally-administered territories of Chandigarh and Pondicherry.
The BBC's Subir Bhaumik in Calcutta says there have been election clashes in seven places in and around the city, with one person reported dead and 17 injured. There were similar clashes there in last week's voting phase.
All 39 constituencies in the southern state of Tamil Nadu are voting.
Tamil Nadu - where voters tend to hand big victories to one or other of the state's two main parties - is expected to play a crucial role in the formation of the government in the coalition talks that are almost certain to follow the election.
The last five governments have been formed with the winners in Tamil Nadu.
Former state chief minister, J Jayalalitha, head of the AIADMK party and one of India's most colourful and controversial politicians, has cast her vote in the state capital Madras (Chennai) and complained of election irregularities.
She said some election machines were not working properly and in some places paramilitaries were nowhere to be seen.
In Jammu and Kashmir, some separatist groups have called for a boycott of the elections and there has been a two-day strike in the Muslim-majority Kashmir valley.
A former separatist and head of a faction of the regional People's Conference party, Sajjad Lone, has broken ranks to stand for election from Baramullah.
The BBC's Altaf Hussain in Srinagar says turnout in the region is so far very low.
A large number of police and paramilitary troops have been deployed in the capital, Srinagar, to prevent anti-election demonstrations, our correspondent says.
Among the other candidates facing the electorate on Wednesday are Varun Gandhi and Mohammad Azharrudin.
Mr Gandhi, who has been accused of making a controversial anti-Muslim speech, is standing for the Bharatiya Janata Party in Pilibhit in Uttar Pradesh.
Ex-cricketer Azharruddin stands for Congress in Moradabad in the same state.
The first round of the general election on 16 April was marred by Maoist attacks in eastern and central India which killed at least 17 people. Later rounds were less violent.
About two million security personnel are being deployed for the five-phase vote.
The new parliament has to be constituted by 2 June.
