West Bengal Assembly election results: Did SIR deletions bring down Mamata Banerjee’s 15-year rule?

Three states — West Bengal, Tamil Nadu and Kerala — have rejected the incumbents, ruling in favour of the opposition parties. In Bengal, the BJP seems poised to win more than 200 seats, while the TMC has been reduced to less than 90 seats.

While the saffron party has a vote share of 45.71 per cent, Mamata Banerjee’s party has gained 40.82 per cent vote share, as per the Election Commission (EC) trends at 7:20 pm. The Special Intensive Revision (SIR) of electoral rolls was believed to have played a big role in the record voter turnout in this year’s Bengal Assembly elections.

But did it lead to the TMC’s defeat in the polls?

Let’s take a closer look.

The number game

As per the Election Commission’s trends at 7:20 pm, the BJP is ahead in 115 seats in West Bengal and has won 91 seats.

The TMC is leading in 42 seats and has bagged 39 seats.

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The saffron party has won more than 2.7 crore votes. The TMC has gained over 2.4 crore votes, as of now.

BJP supporters celebrate as early trends show their party leading in the West Bengal Assembly election results, outside the party's regional office in Kolkata, May 4, 2026. Reuters

There is a gap of over 29 lakh votes between the two parties, leading to a difference of over 120 seats.

The Congress is expected to win just two constituencies with a 3.04 per cent vote share.

Did SIR script Mamata’s defeat?

The EC’s SIR resulted in the deletion of 91 lakh names from West Bengal’s electoral rolls, with the overall electorate falling by 11.63 per cent. These include the names of around 27 lakh people whose appeals remain pending before tribunals.

Of these, only 139 were added back to the voter rolls by the tribunals, while the remaining were not allowed to vote in these elections despite having cast their ballots in the past.

This time, the number of valid electors for the Bengal Assembly polls was 6.81 crore.

As per CNN-News18, even if a fraction of the excluded voters leaned in a particular political direction, the impact on results at the constituency level could be significant.

This explains how a narrow gap in vote share leads to a wide difference in the number of seats.

In the 2021 West Bengal Assembly elections, the TMC was ahead of the BJP by nearly 60 lakh votes, with a vote share gap of about 10 percentage points. This converted into a seat advantage of more than 140 seats.

As per CNN-News18, the BJP has an advantage in 36 of the 54 seats categorised under 'SIR deletions more than 5%', a jump of 18 seats compared to the 2021 polls.

The Trinamool Congress and its alliance are ahead in 18 seats, losing 18 others they previously won to the saffron party. There has been no change in the performance of the Congress and others in these seats, as they remain at zero.

In the 2021 West Bengal Assembly election, the same 54 seats delivered different outcomes. The TMC bagged 36 of these constituencies with a vote share of 46.59 per cent, while the BJP secured 18 seats with 39.61 per cent vote share.

Decoding TMC's defeat beyond SIR

SIR cannot be solely blamed for the TMC’s defeat.

After 15 years of rule, there was an anti-incumbency wave against Chief Minister Mamata Banerjee.

The BJP also targeted the ruling party over alleged corruption and unemployment issues. It appears Banerjee’s efforts to label the saffron party as an ‘outsider’ did not resonate with Bengal's voters.

To counter this narrative, the BJP leaders were seen eating fish in public and even Prime Minister Narendra Modi was filmed munching on jhalmuri.

The saffron party also seems to have wooed women voters, who were a large force behind Didi’s victory for the past 15 years.

The BJP also consolidated Hindu votes, while the TMC continued its dominance in Muslim-majority areas.

However, this seems to have limited her outreach among Hindu voters.

The Matua community rallied behind the BJP despite being impacted by SIR deletions.

With inputs from agencies