Voting for three Lok Sabha seats - Phulpur and Gorakpur in Uttar Pradesh and Araria in Bihar - where major opposition parties have fielded joint candidates against the ruling Bharatiya Janata Party (BJP) will take place on Sunday.
Polling for Bihar's Araria Lok Sabha seat and the Assembly constituencies of Jehanabad and Bhabhua passed off peacefully with an average 54 per cent voting on Sunday. Mr Taslimuddin's death necessitated the by-election on this seat.
The battle in Jehanabad was between the ruling JD (U)'s Abhiram Sharma and RJD's Suday Yadav, son of late Munkrika Yadav who had won the seat in the 2015 Assembly polls.
BJP has fielded Pandey's wife Rinky Rani for the seat while the Congress has fielded Shambhu Singh Patel.
While campaigning for his party's candidate at a public meeting at Narpatganj on March 9, Rao allegedly said, if the RJD candidate wins this election, Araria will become a safe haven for the ISIS.
The Bihar by-election is the first electoral battle in the state since last year's realignment when Chief Minister Nitish Kumar, who also heads the JD (U), left the Grand Alliance and reunited with the BJP.
Chief Minister Yogi Adityanath was among the early voters in Gorakhpur.
The polling mostly went peaceful except for 10-12 rounds of firing between two groups at booth number 94 for the Jahanabad Assembly bypoll.
Also, in Araria, a seat that fell vacant after the death of RJD lawmaker Mohd Taslimuddin, the party has fielded his son Sarfaraz Alam, looking to capitalize on Muslim and Yadav voters who make up a big chunk of the electorate.
JD (U) had initially stated that it will not contest the bye-elections but later relented at BJP's urging to contest from Jehanabad.
Janata Dal (United) is contesting the Jehanabad assembly seat, leaving Araria and Bhabua to its ally, the BJP. There were seven candidates in the fray in Araria, the third most important being Victor Yadav of Pappu Yadav's Jan Adhikar Party (JAP).