The results of this phase are crucial for the Congress, which had bagged five of the six seats in 2009 from the constituencies that have gone to the hustings Thursday.
The other seat - Balurghat - had gone to RSP five years back.
West Bengal has 42 Lok Sabha constituencies, of which four voted April 17.
The next three phases of polling will be held April 30 (nine seats), May 7 (six seats) and May 12 (17 constituencies).
