Over 19 per cent polling was recorded in the first three hours in the by-poll to Kolkata Dakshin Lok Sabha constituency, which was vacated by Chief Minister Mamata Banerjee following her election to the state assembly.
Polling picked up as the day advanced, officials said. "Voting is going on peacefully in all parts of the constituency and no untoward incident has been recorded so far," Jt Commissioner of Police (Headquarters) Jawed Shamim said.
The by-election will see a direct contest between the ruling Trinamool Congress and Communist Party of India (Marxist).
The fight will be between Trinamool's state president Subrata Bakshi and Ritabrata Banerjee of CPI(M). Besides, three Independents are also in the fray in the constituency, which has an electorate of 15.60 lakh.
Bharatiya Janata Party and Trinamool's ally Congress have not put up candidates. The seat fell vacant after Banerjee resigned as MP and successfully fought the Assembly by-election from Bhowanipore for her maiden entry into the state legislature.
The constituency is locally known as the chief minister's pocket borough -- Banerjee has won here six times in a row since 1991. The polling which is being held over seven Assembly segments constituting the Lok Sabha seat began from 8 AM and would end at 5 PM.
State chief electoral officer Sunil Gupta said of the total 1,902 booths, 325 have been declared sensitive and 335 hypersensitive.
Gupta said that 118 sector officers would oversee the security in the constituency.
