The Opposition’s fragmented contest in the Brihanmumbai Municipal Corporation (BMC) elections helped the BJP-Shinde Sena Mahayuti alliance turn even narrow vote-share leads into a decisive advantage in seats under the first-past-the-post system, an analysis of vote-share data by The Indian Express shows.

Under the the first-past-the-post system, candidates do not need a majority to win. Even a narrow lead in absolute votes can be enough if the rest are split among rivals.

While the gap in vote share between the ruling alliance and the main Opposition parties (when counted as a bloc) was narrow in the recently-concluded BMC elections, the difference in the number of seats won was significant.

The Shiv Sena (UBT), Congress, NCP (Sharad Pawar) and the Maharashtra Navnirman Sena (MNS) together polled about 23.06 lakh votes, or 42.01% of the total votes cast, which was more than roughly 22.38 lakh votes, or rounds to 41%, polled by the Mahayuti alliance.

While the ruling Mahayuti went into the BMC elections as a formal alliance with the BJP contesting 137 of the 227 wards and the Shiv Sena fighting on 90 seats, the Opposition Maha Vikas Aghadi adopted a contrasting strategy.

Despite being alliance partners, the Shiv Sena UBT and the Congress largely contested the polls independently, fielding candidates in a significantly higher number of wards with 163 and 152 seats respectively.

Yet the BJP–Shinde Sena combine went on to win 118 of the 227 wards, crossing the halfway mark and securing control of India’s richest civic body, while the Sena (UBT), Congress, NCP-SP and the MNS together won 96 wards.

Across Mumbai’s 227 wards, a total of 54.64 lakh votes were polled.

The data also shows how vote division among Opposition parties may have worked to the ruling alliance’s advantage across the city.

While the BJP and the Shiv Sena typically faced a single main challenger in each ward, Opposition votes were often split between two or three candidates, potentially proving costly in contests decided by narrow margins.

In Dahisar West (Ward 1), for instance, the Shinde Sena candidate won with 7,544 votes. The Congress candidate polled 5,070 votes, while the Shiv Sena (UBT) candidate secured 4,314. Together, the two Opposition candidates polled 9,384 votes — nearly 1,900 more than the winner — but lost the ward because they contested separately.

The winning margin was 2,474 votes. Similar patterns were seen across Mumbai.

How parties fared

A comparison of vote numbers from the 2017 and 2026 BMC elections shows that the BJP’s vote share rose only slightly. In 2017, the BJP polled 13.94 lakh votes, or 27.32 per cent of the total votes. In 2026, its vote count increased to 15.40 lakh votes, taking its share to 28.2 per cent, becoming the single largest party. The rise was small, but the party was able to keep its supporters united.

In 2017, the BJP had contested almost all the Corporation seats managing to draw 27.32 per cent of the votes. This time is fought on 137 relatively lesser than last time around but managed to consolidate its bases getting 28.2 per cent of the vote inspite of contesting on far fewer constituencies

In 2017, the undivided Shiv Sena was the largest party, polling 14.43 lakh votes and securing 28.29 per cent of the vote. By 2026, the party had split. The Eknath Shinde led Shiv Sena polled 6.93 lakh votes, or 12.8 per cent, while the Shiv Sena UBT secured 13.16 lakh votes, or 24.2 per cent.

Together, the two Sena factions received about 20.1 lakh votes, which is around 4.3 lakh votes more than what the undivided Shiv Sena had polled in 2017.

The Congress also lost support. In 2017, it polled 8.13 lakh votes, or 15.94 per cent. In 2026, its vote count fell to 6.26 lakh votes, reducing its share to 11.5 per cent.

The Maharashtra Navnirman Sena saw a smaller drop. It polled 3.33 lakh votes in 2026, down from 3.94 lakh votes in 2017. Its vote share fell from 7.73 per cent to 6.1 per cent.