Polling was sluggish in Rampur Sadar with the assembly segment, earlier held by Samajwadi Party leader Azam Khan, registering around 31.22 per cent turnout in the by-election till 5 pm on Monday.

Mainpuri parliamentary constituency, which fell vacant after the death of Samajwadi party patriarch Mulayam Singh Yadav, registered 51.89 per cent voting. Khatauli Assembly segment in Muzaffarnagar recorded 54.50 per cent polling.

Polling began at 7 am and is scheduled to end at 6 pm. The BJP and Samajwadi Party, the two main contenders, have accused each other of disrupting the electoral process. Delegations of both parties met Chief Electoral Officer Ajay Kumar Shukla alleging rigging.

Samajwadi Party state president Naresh Uttam Patel and spokesperson Rajendra Chaudhary along with senior leaders, including MLA Manoj Pandey, gave a memorandum addressed to the Election Commission alleging rigging by the administration and the police in all the three bypolls.

In the memorandum, the party also accused the administration of preventing the voters from casting their votes.

The Samajwadi Party, on its official Twitter handle also, alleged that the police force was being used and officials on election duty were preventing people from casting their votes, especially in Rampur.

In a video posted on the microblogging site, it alleged that BJP agents were distributing money in Mainpuri's Bhogaon area.

At a press conference in Saifai, Samajwadi Party chief Akhilesh Yadav accused the BJP government of misusing the official machinery. He alleged that the Rampur administration and the police were not allowing people to come out and vote.

On the other hand, BJP also submitted a memorandum to the Chief Electoral Officer demanding action in the Mainpuri Lok Sabha by-election, accusing the Samajwadi Party of spreading anarchy and influencing voting.

The delegation led by the party's State General Secretary J P S Rathore told the Chief Electoral Officer that "confusion is being spread by the Samajwadi Party in Mainpuri by giving wrong information".

"The issues on which the party is registering its complaints are all false. In this guise, pro-BJP workers are being intimidated by Samajwadi Party's anarchists in Mainpuri Lok Sabha constituency," the BJP alleged.

BJP state president Bhupinder Singh Chaudhary said, "The Samajwadi Party is making baseless allegations as it is going to taste defeat in all the three seats." The party took to Twitter to allege that in some booths, "unscrupulous elements of the Samajwadi Party" were preventing people from casting their votes and sought the Election Commission's intervention.

The bypolls are witnessing a direct contest between the ruling BJP and the opposition Samajwadi Party-Rashtriya Lok Dal (RLD) alliance. The BSP and Congress are not in the fray.

In a tweet, Chief Minister Yogi Adityanath appealed to the people "to vote for security, development and good governance".

As many as 24.43 lakh people -- 13.14 lakh men, 11.29 lakh women and 132 third gender -- are eligible to exercise their franchise in Mainpuri parliamentary and Rampur and Khatauli Assembly bypolls.

The by-election to the Mainpuri Lok Sabha seat is taking place due to the death of Samajwadi Party founder Mulayam Singh Yadav.

The Rampur Sadar and Khatauli Assembly bypolls were necessitated after Samajwadi Party MLA Azam Khan and BJP legislator Vikram Singh Saini were disqualified following their conviction in separate cases. Rampur has a sizeable Muslim population.

While Khan, the most prominent Muslim leader of the Samajwadi Party, was disqualified from the Uttar Pradesh Assembly after a court awarded him a three-year imprisonment in a 2019 hate-speech case, Saini was disqualified following his conviction in a case related to the 2013 Muzaffarnagar riots.

Following defeats in Azamgarh and the Rampur Lok Sabha bypoll, considered the Samajwadi party bastions, the Mainpuri parliamentary and Rampur and Khatauli Assembly by-elections have become crucial for the Akhilesh Yadav-led party. Six candidates are in the fray in Mainpuri, 14 in Khatauli and 10 in Rampur Sadar, according to the Election Commission.

In Mainpuri, Samajwadi Party president Akhilesh Yadav's wife Dimple Yadav is pitted against BJP's Raghuraj Singh Shakya, once a close associate of Shivpal Singh Yadav.

Shakya joined the BJP ahead of the Uttar Pradesh assembly polls held earlier this year.

In the Rampur Sadar Assembly segment, the BJP has fielded Akash Saxena, the son of former party legislator Shiv Bahadur Saxena, against Azam Khan's protege Asim Raja.

In Khatauli, the fight is between Vikram Singh Saini's wife Rajkumari Saini and Madan Bhaiya of the Rashtriya Lok Dal.

The counting of votes is on December 8.

The outcomes of the bypolls will not have any impact on the Central or the state governments as the BJP enjoys a comfortable majority at both levels. However, a win would provide a psychological advantage ahead of the 2024 parliamentary elections.