Here are more updates:
7.00 pm: 82.50% voter turnout recorded till 6 pm.
Constituency-wise turnouts: Howrah: 73.43%, Uluberia: 81.11%, Arambag: 84.25%, Srerampore: 77.06%, Bolpur: 82.55%, Hooghly: 82.56%, Birbhum: 84.9%, Bardhaman Purba: 84.05%, Bardhaman-Durgapur: 83.74%
6.40 pm: 9 persons injured in clash in Kalna in Bardhaman Purba constituency West Bengal, 6 among them are Trinamool supporters.
5.35 pm: West Bengal records 79.6% voter turnout till 5 pm.
5.02 pm: Trinamool supporters accused on giving life threats to villagers of Ketugram in Bolpur Lok Sabha constituency.
4.47 pm: Constituency-wise turnout: Howrah - 62.56%, Uluberia - 71%, Hooghly - 71.87%, Serampore - 68.24%, Arambagh - 77.09%, Birbhum - 72.33%, Bolpur - 73.12%, Bardhaman East - 74.16%, Bardhaman Durgapur - 73.26%
4.25 pm: CPI(M) agent driven out by Trinamool supporters in a booth in Ketugram under Bolpur constituency in West Bengal.
4.00 pm: EVM snatched in a polling booth in Uluberia constituency.
3.30 pm: 72.65% voter turnout in West Bengal till 3 pm.
3.20 pm: Narendra Modi not a good prime ministerial candidate, says Nobel laureate Amartya Sen after casting its poll.
3.15 pm: What can we do if bombing takes place outside booths, asks West Bengal poll observer Sudhir Kumar Mishra.
3.00 pm: West Bengal BJP leader Shamik Bhattacharya allegedly beaten up.
2.48 pm: Four voters were seriously injured after alleged Trinamool goons attack a booth in Sadaipur in Birbhum.
2.45 pm: Left Front decides to send delegation under Sitaram Yechury to meet EC members in New Delhi.
2.44 pm: Polling taking place in various booths in the absence of central forces.
2.30 pm: Bombs were hurled outside two booths to scare the voters away in Ketugram under Bolpur constituency in West Bengal. The police reportedly snatched cameras of the photographers.
"About 44 per cent polling was recorded on an average in the first four hours of polling in nine Lok Sabha constituencies of Howrah, Uluberia, Serampore, Hooghly, Arambagh, Burdwan (East), Burdwan-Durgapur, Bolpur and Birbhum," state's Chief Electoral Officer (CEO) Sunil Gupta said.
The polling percentage was very good in the first four hours and a large number voters were waiting in queues in most polling stations, he said.
Polling was peaceful and incident-free, the CEO said. Some EVMs had to be replaced after mock polling.
Arrangements were made for webcasting and live monitoring of sensitive areas amid tight security provided by central forces which were more than double than the 2011 Assembly election.
Bye-election in Galsi (SC) Assembly seat in Burdwan district was also being held.