The campaign for six by-elections across West Bengal, Tamil Nadu, Assam and Puducherry ended on Sunday, setting the stage for voting on October 6 in five Assembly constituencies and one Lok Sabha seat.
The contests in Nandigram and Rejinagar in West Bengal, Madurantakam and Dharapuram in Tamil Nadu, Thattanchavady in Puducherry and Nagaon in Assam are being closely watched as early tests of the political strength of governments and parties that came to power or consolidated their positions after the April 2026 elections. The results will be declared on October 9.
All six vacancies were created after the April elections, when several candidates won from two constituencies and subsequently retained one, requiring the other seats to be filled through by-elections.
Bengal contests carry battles over power and organisation
Nandigram is among the most politically watched contests, with Chief Minister Suvendu Adhikari having vacated the seat after retaining Bhabanipur, where he defeated TMC supremo Mamata Banerjee.
The BJP has fielded Hasirani Rath, the mother of Adhikari's slain close aide Chandranath Rath. Adhikari led a foot march in Nandigram on Sunday in her support and used the final campaign hours to revive allegations against the previous TMC government over the 2021 election period.
He alleged that the earlier TMC government had “misused” the CID to frame BJP leaders in an attempt-to-murder case following what he described as Banerjee's “false claims” about a leg injury during the 2021 polls.
“Under the previous TMC government, the CID harassed BJP leaders entirely on falsehoods. Attempt to murder charges were framed against them even though official documents do not show any fracture,” Adhikari said.
TMC MLA Kunal Ghosh questioned why the allegation had been raised just before the bypoll.
Banerjee remains Adhikari's principal political rival even though she is not contesting the Nandigram bypoll. Her TMC faction had initially nominated Sanchita Pradhan Dey but she withdrew after a meeting with Adhikari. The party subsequently extended its support to Congress candidate Milan Pradhan.
Pradhan's campaign was further complicated by his arrest in September in six cases dating back to the 2007 Nandigram land agitation. The Calcutta High Court later granted him interim bail, allowing him to return to the constituency shortly before campaigning ended. The Supreme Court was also approached by the West Bengal government over the bail, with the matter scheduled for October 5.
The bypolls are also taking place against the backdrop of unresolved Special Intensive Revision-related appeals. More than 18,000 such appeals were pending in Nandigram and Rejinagar in the run-up to polling, adding another layer of electoral controversy.
Rejinagar sees a fractured opposition contest
Rejinagar became vacant after Aam Janata Unnayan Party founder Humayun Kabir won both Rejinagar and Nawda in the Assembly election and retained Nawda.
His son, Golam Nabi Azad, is contesting the bypoll for AJUP. The other prominent candidates include TMC's Rabiul Alam Chowdhury from the Mamata Banerjee faction, Safiuzzaman Sheikh from the rebel faction led by Ritabrata Banerjee, and Congress's Mohd Abdullahil Kafi.
The fragmented field has made opposition unity a key issue. TMC's Kunal Ghosh said the opposition had not formed an alliance with Congress and CPI(M), acknowledging that opposition votes could be divided, but argued that all parties had a responsibility to protect polling booths and voters' rights.
Adhikari, meanwhile, campaigned in the Muslim-majority constituency and urged voters not to pay heed to the “70:30” communal narrative. He also promised projects including a 200-bed hospital, an industrial park, a new bridge and a college, while pledging to help bring back 40,000 migrant workers over two years.
The Nandigram and Rejinagar contests have also seen legal and organisational battles, including an unsuccessful challenge by the Indian Secular Front against the Election Commission's allocation of the envelope symbol to the Democratic Trinamool Congress.
Vijay puts his political weight behind two Tamil Nadu seats
The two Tamil Nadu bypolls are particularly important for Chief Minister C Joseph Vijay and his Tamilaga Vettri Kazhagam (TVK), which is facing its first major electoral test after forming the government.
Madurantakam and Dharapuram are both reserved constituencies. Former AIADMK MLAs K Maragatham Kumaravel and P Sathyabama had won the seats in the April Assembly election before resigning and joining Vijay's TVK. The party has now nominated both of them from their respective constituencies.
The principal rivals include DMK candidates I Paranthamen in Madurantakam and S Suganya in Dharapuram, while AIADMK has also fielded candidates in both seats.
Vijay devoted considerable time to the campaign. He conducted a roadshow covering more than 30 villages and about 45 km in Madurantakam, where he also drove a tractor and stopped at a roadside tea shop to interact with residents.
In Dharapuram, he held a 40-km roadshow for Sathyabama before campaigning ended.
The chief minister used the final campaign days to attack the DMK over remarks directed at women, saying political criticism had “crossed the line” and that he would not remain silent. Vijay and his party described remarks targeting Sathyabama as body-shaming and criticised what they called crude rhetoric in Tamil Nadu politics.
The contests have also become a test of the strength of the emerging political equations around Vijay's government, with the DMK, AIADMK and Left parties competing alongside the TVK.
The campaign was not without controversy. Police registered a case against Opposition Leader Udhayanidhi Stalin over the alleged involvement of a minor in an election campaign event in Dharapuram. He had also accused the ruling TVK of distributing cash to voters, an allegation that added to the tensions surrounding the contest.
Nagaon becomes a three-way battle in Assam
The Nagaon Lok Sabha seat fell vacant after Congress MP Pradyut Bordoloi resigned from the party, joined the BJP and subsequently won the Dispur Assembly seat in the April polls.
The BJP has fielded former bureaucrat Devasish Sharma, while Congress is seeking to retain the seat and the AIUDF is mounting its own challenge.
Chief Minister Himanta Biswa Sarma acknowledged that Nagaon would be difficult for the BJP because Muslims account for a majority of voters, but expressed confidence that Sharma could win by between 250,000 and 300,000 votes.
Congress state president Gaurav Gogoi said he was “100% confident” that Congress would retain the constituency, arguing that voters seeking to defeat the BJP would have to support Congress.
AIUDF chief Badruddin Ajmal also claimed confidence, saying his party's contest was against both the BJP and Congress and predicting a victory margin of around one million votes.
The contest has become a major three-way political battle, with the BJP seeking to consolidate its post-Assembly election position, Congress attempting to stage a comeback and AIUDF trying to regain influence among Muslim voters.
The final days also saw the rhetoric intensify. Sharma filed a police complaint against Ajmal after the AIUDF leader allegedly described him as a “murderer” and “killer” during campaign speeches.
At the same time, the BJP-led candidate received an unexpected boost when the All-Assam Minority Students' Union publicly backed Sharma and appealed to minority voters to support him in the name of development.
Thattanchavady tests Rangasamy's hold
In Puducherry, the Thattanchavady Assembly constituency is witnessing an 11-cornered contest after Chief Minister N Rangasamy vacated the seat and retained Mangalam, which he had also won in the April election.
Rangasamy has represented Thattanchavady since his first electoral victory there in 1991. The AINRC has nominated former legislator Ashok Anand, who is backed by the BJP, AIADMK and Lakshiya Jananayaga Katchi.
The main opposition candidates include DMK's K Sethu Selvam, CPI's M A Saleem and Congress's E Vinayagam, who has the backing of Vijay's TVK. Naam Tamilar Katchi has fielded S Karthi Kumari.
The constituency has around 27,000 voters and has traditionally been regarded as a stronghold of Rangasamy. The final campaign saw NDA leaders, including Rangasamy and Home Minister A Namassivayam, take part in motorcycle rallies and door-to-door campaigning, while DMK president M K Stalin appealed through a video conference for voters to support his party's candidate.
The Thattanchavady result will therefore be closely watched as a measure of whether Rangasamy's personal political hold can be transferred to the AINRC candidate.
Six contests, different tests for ruling parties
Although the six bypolls are geographically dispersed and involve different local political equations, they share a common significance. They offer an early opportunity to measure whether the momentum of the April elections has continued into the first major round of post-election contests.
For Suvendu Adhikari, Nandigram is a test of his political dominance in a constituency that remains closely associated with his rivalry with Mamata Banerjee. Rejinagar will test how a fragmented opposition performs against the BJP-backed ruling establishment.
In Tamil Nadu, Vijay's decision to campaign extensively in two constituencies makes the results an early test of the TVK government's popularity and organisational strength. In Assam, Nagaon pits the BJP, Congress and AIUDF against one another in a constituency where demographic calculations are central to the contest.
In Puducherry, the focus is on whether Rangasamy's AINRC can retain a constituency the chief minister himself vacated.
With campaigning now over, voters in all six constituencies will decide on October 6 whether the parties that emerged victorious in the April elections can sustain their momentum in the first major bypoll test of the new political cycle.