The by-election to the Araria seat was necessitated by the death of RJD MP Mohd Taslimuddin. The contest is mainly between RJD's Sarafaraz Alam, Taslimuddin's son, and BJP's Pradip Singh, who had won the seat in 2009 and lost in 2014.
In Jehanabad, the RJD hopes to retain the Assembly seat that fell vacant after the death of Mundrika Yadav. The party gave ticket to Yadav's son Kumar Krishna Mohan.
The BJP is hopeful of retaining the Bhabhua Assembly seat riding on a sympathy wave for Anand Bhushan Pandey whose death at the age of 48 necessitated the bypoll. The saffron party fielded Pandey's wife Rinky Rani.
This is the first electoral battle in the state since Chief Minister Nitish Kumar, who also heads the JD(U), walked out of the alliance with the RJD and the Congress and joined the BJP-led NDA last year.