Sri Lanka, April 23 -- Voters will cast their ballots on Thursday as high-stakes state elections get under way across India, with key contests in West Bengal and Tamil Nadu.

In West Bengal, where the fiercest contest is unfolding, voting will be held in 152 of 294 seats across 16 districts in the first phase, with 1,478 candidates in the fray.

Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) has mounted an aggressive push to unseat Chief Minister Mamata Banerjee, whose Trinamool Congress is seeking a fourth straight term in a state the BJP has never governed.

A second phase of polling is scheduled for next week.

The election is taking place against a controversy over a sweeping revision of electoral rolls, which has heighte...