The byelections are scheduled to be held on March 11.
Within four years of winning a single party majority in the Lok Sabha with 282 seats -- the first time it has happened in 30 years -- the BJP has lost it.
The bypolls were necessitated after Chief Minister Yogi Adityanath and deputy chief minister Keshav Prasad Maurya vacated their seats following their election to the Uttar Pradesh legislative council.
The bypolls are termed as a 'rehearsal' for the 2019 Lok Sabha polls by CM Yogi Adityanath.
CM Yogi Adityanath said the BJP was getting widespread support from the people.