Two days after raising concerns about suspicious voter additions and deletions during the Maharashtra Assembly election, psephologist Sanjay Kumar of the Centre for the Study of Developing Societies (CSDS) apologised and deleted his posts, which triggered a political row.

The BJP accused the research organisation of releasing unverified data to support the Congress's "false narrative". The principal Opposition responded that while it had cited CSDS numbers, it had also verified them with independently obtained evidence.

Sanjay Kumar unexpectedly removed his tweets pointing to sudden spikes and dips in voter numbers across certain Assembly constituencies in Maharashtra and apologised for the "mistake".

"I apologise genuinely for the tweets that were tweeted on the Maharashtra elections. Miscalculation happened while matching data of 2024 LS and 2024 AS. Our data team read the raw data wrongly. The tweet is now deleted. I never intended to spread any kind of misinformation," he posted on X.

Earlier, the psephologist had said the voter base in Nashik West and Hingna constituencies increased by 47 per cent and 43 per cent, respectively, between the 2024 Lok Sabha election and the Maharashtra election. He also said the voter base dropped sharply in Ramtek and Devlali by 38 per cent and 36 per cent, respectively.

These allegations energised the Congress campaign of 'vote fraud' against the BJP and were shared by its senior leadership to target the ruling party. With Sanjay Kumar now retracting his claims and apologising, the BJP countered.

Senior BJP leader and party IT head Amit Malviya said that the institution Rahul Gandhi, Leader of the Opposition in Lok Sabha, relied on for his charges, had itself admitted its figures were wrong. "Where does that leave Rahul Gandhi and the Congress, which made blatant attacks on the Election Commission and even went so far as to label actual voters as fake ones? Shameful," Mr Malviya stated, demanding an apology from the Congress leader.

Sanjay Kumar’s apology came as the Opposition was already accusing the Election Commission of colluding with the BJP to benefit the ruling party. Rahul Gandhi cited 'vote theft' in Karnataka’s Mahadevapura constituency and alleged abnormalities in the Maharashtra poll. The INDI alliance, which had won 30 of the 48 Lok Sabha seats in Maharashtra a year earlier, failed to cross 50 seats in the state assembly polls held five months later.

The Election Commission rejected the charges and asked Rahul Gandhi to file an affidavit reaffirming his claims or issue an apology.

Despite Sanjay Kumar’s retraction, the Congress stood by its allegations. Party leader Sujata Paul told NDTV that CSDS was only one of its sources. "As far as we are concerned, we may have adopted this data, but we have also verified it with evidence which we have received from our sources, our workers, and the whole opposition that was contesting the elections together in Maharashtra," she said.

"The CSDS data was only utilised as supporting evidence. And why he (Sanjay Kumar) apologised, that is his issue, not ours," she said.