Varanasi, India (BBN)-Voting has begun in the battleground of Varanasi as India votes in the final phase of its mammoth general election.

The main opposition BJP's leader Narendra Modi remains a front-runner in the seat, but is being challenged by Arvind Kejriwal of the new anti-corruption Aam Aadmi Party (AAP), reports BBC.

Voting is due in 41 seats on Monday in the states of Uttar Pradesh, Bihar and West Bengal.

The nine-phase election began on 7 May. Vote counting is due on 16 May.

With 814 million eligible voters, India's election is the world's biggest exercise in democracy and the governing Congress party is battling the opposition Bharatiya Janata Party (BJP) for power.

Modi is ahead in all the opinion polls.

'EPIC BATTLE'

Varanasi has seen a frenzy of political campaigning not seen in the ancient city in decades, says the BBC's Soutik Biswas.

Modi is being given a spirited fight by Kejriwal whose army of volunteers is engaged in extensive door-to-door campaigning.

There are a total of 42 candidates in the fray in the seat, including the Congress party's Ajay Rai, a local political leader.

Correspondents report this seems to be the most prestigious battle in the elections – top leaders from the BJP, Congress and AAP have all campaigned here for their candidates in the past weeks.

"This is a very politically conscious city. The epic battle between Modi and Kejriwal has pulled the city out of political oblivion," says Dr Vishwanath Pandey, who teaches at the Benares Hindu University.

Varanasi has been turned into a fortress with thousands of police and paramilitaries deployed to ensure peaceful polling.

The state of Uttar Pradesh, where Varanasi is located, returns more MPs than any other and is often described as India's battleground state.

Varanasi, on the banks of the Ganges river, has long been neglected despite its religious significance and suffers from dismal infrastructure.

Both Modi and Kejriwal have promised to work for the city's development if elected.

BBN/SS/AS-12May14-10:00am (BST)