Low turnout marked India's most high-profile bypoll held in the eastern state of West Bengal's capital Kolkata on Thursday.

Till evening, a little over 53 percent voters cast their ballots in the by-election to the Bhawanipur seat in south Kolkata, where Bengal Chief Minister Mamata Banerjee is contesting to retain her constitutional post.

Polling began at 7am amid tight security and Covid-safety protocols.

The by-elections to two more seats in Bengal -- Jangipur and Samserganj in Murshidabad district -- were also held on the same day. 

Nearly seven lakh people were eligible to cast their ballots in the constituencies. The results will be out on October 3.

In Bhawanipur, 66-year-old Mamata has to pull off a win to continue as Bengal CM.  India's ruling and Bengal's main opposition Bharatiya Janata Party (BJP) has pitted a little-known woman lawyer against Mamata.

Though her Trinamool Congress party swept back to power in Bengal in May's assembly polls, Mamata lost her own seat in Nandigram to her protege-turned-rival Suvendu Adhikari by around 2,000 votes. 

Mamata has, however, challenged Suvendu's election in the Kolkata high court.

India's main opposition Congress, on the other hand, has not fielded any candidate against Mamata. The party's decision was announced by West Bengal Congress chief Adhir Ranjan Chowdhury earlier this month.

On May 2, Mamata single-handedly pulled off a landslide victory in the assembly election for the third time in a row, bucking anti-incumbency and staving off a massive challenge from Prime Minister Narendra Modi's Bharatiya Janata Party (BJP).

In June, Mamata moved the high court to declare Suvendu's election win "null and void' on the grounds that he had indulged in corrupt practices and sought votes on the basis of religion. 

"Suvendu Adhikari has indulged in several corrupt practices that have enhanced his winning chances and materially altered Mamata Banerjee's chances of success in the election," her petition read.

In her petition, Mamata also alleged discrepancies in the counting of votes, Mamata's lawyer had said.

West Bengal had witnessed the most high-profile contest in India's recently held state elections. While Mamata harped on being Bengal’s daughter, the BJP asked people to vote for "change and development" after 50 years of Communist and Trinamool rule.