The 18 poll-going constituencies include- nine in Purulia, three in Bankura and six in West Midnapore.
In 13 Left Wing Extremism (LWE) affected constituencies, polling will end two hours early at 4 p.m.
As many as 40,09,171 electors including 16 transgender voters will exercise their franchise in the first stage which has 133 candidates in the fray.
The staggered six-phase elections for 294 assembly seats are spread over seven polling dates and will continue till May 5.
The other six polling dates are April 11, 17, 21, 25, 30 and May 5.
