West Bengal’s political battle is set to move from the Assembly to the Rajya Sabha, with the Election Commission announcing October 16 as the date for the by-election to the seat vacated by former Trinamool Congress MP Koel Mallick. The timing places the contest in the middle of Durga Puja, with polling scheduled for Durga Shashthi.
The by-election comes at a politically significant moment for Bengal. The 2026 Assembly election dramatically altered the state’s political arithmetic, with the BJP winning 208 of the 294 seats and the TMC reduced to 80, according to election results compiled by The Indian Express.
That changed Assembly arithmetic is now directly relevant to the Rajya Sabha contest because the Upper House seat will be decided by elected legislators rather than through a direct popular vote.
BJP-TMC Numbers Under the Spotlight
The vacant seat was created after Mallick resigned as a Rajya Sabha member on July 16, just months after being elected to the Upper House on a TMC ticket. Her resignation followed a series of political departures and defections involving TMC leaders after the Assembly election.
The contest therefore comes amid a wider realignment in Bengal politics. Several former TMC Rajya Sabha MPs, including Sushmita Dev, Sukhendu Sekhar Ray and Prakash Chik Baraik, subsequently joined the BJP after resigning from the Upper House.
The October by-election will consequently be watched not merely as a vacancy-filling exercise but as an early test of the post-Assembly political arithmetic inside the Bengal legislature.
Who Gets the TMC Seat?
The immediate political question is who the BJP and TMC will field for the vacant seat.
Mallick's resignation has already generated speculation over whether she could return to the Rajya Sabha from the BJP side. Anandabazar reported that discussions around her political future began after her resignation, while other reports have linked her to the BJP. No final candidature, however, has been announced by the Election Commission or either party in the sources reviewed.
For the TMC, the vacancy comes at a time when the party is dealing with the consequences of its Assembly defeat and subsequent organisational and parliamentary defections. For the BJP, the contest provides an opportunity to translate its substantially larger Assembly strength into representation in the Upper House.
The Election Commission will issue the notification on September 29. The last date for filing nominations is October 6, followed by scrutiny on October 7. Candidates can withdraw their nominations until October 9.
Polling will take place on October 16 from 9 am to 4 pm, with counting scheduled for the same day.
The Bengal contest is being held alongside Rajya Sabha elections for 10 seats in Uttar Pradesh and one in Uttarakhand. But in Bengal, the political significance extends beyond the single vacant seat: the result will be watched against the backdrop of the state's post-2026 Assembly realignment and the continuing contest between the BJP and the TMC.
With the vote falling during Durga Puja, Bengal's political calendar is set for another closely watched electoral contest just months after the Assembly polls.
