India by-elections: Which six constituencies are voting on October 6?

Voting is under way on October 6, 2026, in six Indian by-elections: the Nandigram and Rejinagar Assembly seats in West Bengal, Madurantakam and Dharapuram in Tamil Nadu, Thattanchavady in Puducherry, and Assam’s Nagaon Lok Sabha seat. Five contests will elect legislators; Nagaon will elect a member of Parliament. Counting is scheduled for October 9.

All six seats became vacant after their elected representatives resigned. In several cases, voters are returning to the polls only months after the April Assembly elections because a winner retained a different constituency or changed parties. The choices are local, even where prominent state leaders have made the campaigns politically significant.

West Bengal: Nandigram and Rejinagar

Nandigram is voting to replace Suvendu Adhikari, who won the seat in the 2026 Assembly election but chose to retain Bhabanipur. Adhikari is now West Bengal’s chief minister, making the by-election a test of whether the BJP can hold the constituency without him on the ballot. The party has fielded Hasirani Rath. Mamata Banerjee’s Trinamool Congress faction is backing Congress candidate Milan Pradhan after its own nominee withdrew; another Trinamool faction and the CPI are also contesting.

Nandigram carries a longer political history: it was central to the land-acquisition movement that helped reshape West Bengal politics, and it was where Adhikari defeated Banerjee in the 2021 Assembly election. Neither Adhikari nor Banerjee is a candidate in this by-election. Voters are deciding who represents the constituency now, not replaying their earlier contest.

Rejinagar, in Murshidabad district, became vacant after Humayun Kabir won two Assembly seats and retained Nawda. His Aam Janata Unnayan Party has nominated his son, Golam Nabi Azad, for Rejinagar. Candidates from the BJP, Congress, CPI(M) and rival Trinamool factions are also in the field. The result will show which of those competing parties and factions secures this particular seat, rather than settle their wider disputes.

Tamil Nadu: Madurantakam and Dharapuram

Madurantakam and Dharapuram are Assembly constituencies reserved for Scheduled Caste candidates. Their elected AIADMK legislators, K Maragatham Kumaravel and P Sathyabama, resigned, joined Chief Minister Vijay’s Tamilaga Vettri Kazhagam (TVK), and are contesting again under their new party’s banner: Kumaravel in Madurantakam and Sathyabama in Dharapuram.

That gives voters a clear question alongside the usual choice of candidate: whether to return the same representatives after their party switch. The AIADMK is seeking to retain voters who backed it in April, while the DMK and other parties are also contesting. These are among TVK’s first electoral tests since it formed the Tamil Nadu government, but neither individual result should be mistaken for a statewide vote.

Puducherry: Thattanchavady

Thattanchavady is voting because Chief Minister N Rangasamy, elected from two seats, retained Mangalam and gave up Thattanchavady. His All India N.R. Congress has fielded Ashok Anand. Congress candidate E Vinayagam and the DMK’s K Sethu, also known as Sethuselvam, are among the other contenders.

The ballot therefore offers voters a choice between the chief minister’s party and several challengers for representation in Puducherry’s Assembly. Rangasamy’s government remains in office; the by-election fills the seat he vacated.

Assam: Nagaon Lok Sabha seat

Nagaon is the only parliamentary constituency voting on Tuesday. Former Congress MP Pradyut Bordoloi resigned, joined the BJP and won an Assam Assembly seat, leaving his Lok Sabha seat open. Congress has nominated former legislator Sibamoni Bora, the BJP has fielded Devasish Sharma, and All India United Democratic Front leader Badruddin Ajmal is also contesting.

The choice determines who will represent Nagaon in Parliament after Bordoloi’s departure. It is also a contest over a seat Congress previously held, with three prominent parties seeking support from the constituency’s voters.

When will turnout and results be known?

Polling began at 7 a.m. local time. Voting is scheduled to end at 5 p.m. in Nagaon and at 6 p.m. in the five Assembly constituencies. No verified constituency-level turnout figures or results were available at the time of this update. Turnout figures, when released, will describe participation—not the outcome. Votes are due to be counted on Friday, October 9.