Before kickstarting the Special Intensive Revision (SIR) of electoral rolls in poll-bound West Bengal, the Election Commission (EC) has started comparing this year’s voters’ list with that of 2002, when the last revision exercise was conducted in the state.

This process of “matching-mapping” is being done by the EC in every electoral district of the state.

Sources in the EC said that so far, it has completed matching-mapping in seven districts and found that 40% to 45% names in the 2025 list were not matching with the 2002 list.

In Jhargram district, only 51.36% of the names in the two voters’ lists matched – the lowest among the seven districts – whereas in the hill district of Kalimpong, the matching was the highest at 65.27%.

In Alipurduar, it was 53.73%, Kolkata North 55.35%, Malda 54.49%, Purulia 61.29%, and Midnapore 62.94%.

“The big and highly populated districts are in South and North 24 Parganas, Kolkata South, and Nadia. In these four districts, we will have to see what percentage of the data will match. That will be significant,” a senior EC official said.

In Bihar, the only state where the SIR has been conducted so far, the latest voter list was compared to the 2003 list, when the revision exercise was last carried out there. All those who did not figure in the 2003 list were required to submit a list of documents for enrolment, which is likely to be implemented in Bengal too.

Deputy Election Commissioner Gyanesh Bharati, who visited West Bengal after the Durga Puja to take stock of the preparations for the SIR, had directed all the district magistrates to complete the matching-mapping process by October 15. However, only seven districts have been able to complete the exercise.

A string of festivals in the state has put a temporary halt to the process, and the SIR of electoral rolls will now most likely begin in November, sources in the EC said.

The EC’s decision to halt the SIR this month comes days after Chief Minister Mamata Banerjee had questioned the “haste shown” by the EC in conducting the exercise even as the state was celebrating a string of festivals. She had also accused the poll panel of acting like a “rubber stamp” of the BJP.

After concluding his two-day visit to the state, Deputy Election Commissioner Bharti had expressed concern over the pace of work and questioned the district administration’s justification for Puja holidays.

According to sources, Bharti had stressed that since SIR was being implemented across the country, there should not be any further delay in conducting it in West Bengal.

The ruling TMC and the Opposition BJP are at loggerheads in the state over conducting the SIR. While the TMC has warned against the deletion of voters’ names, the BJP has argued that SIR would help in weeding out illegal migrants from the voters’ list.