- In Kairana, the BJP has fielded Hukum Singh's daughter Mriganka Singh
- BJP keen on keeping seat that Hukum Singh won
- For Nagaland bypoll, it's a direct contest between two regional fronts
Here are the top 10 developments to the story
In Kairana, the BJP has fielded Hukum Singh's daughter Mriganka Singh to take on Tabassum Hasan who has been propped as the opposition candidate. Ms Hasan was earlier with the BSP, then moved to the SP before joining Ajit Singh's RLD. Her late husband Munnawar Hasan has represented the seat earlier.
On the seat that has 16 lakh voters - nearly a third of them Muslim - the opposition has gone all out to recreate its successes in the bypolls to Gorakhpur and Phulpur, seats earlier held by UP Chief Minister Yogi Adityanath and his deputy Keshav Prasad Maurya. The opposition is also eyeing the chunk of Jat voters, who have traditionally voted for Ajit Singh's RLD but had drifted to the BJP in 2014.
Faced with the opposition onslaught, the BJP is keen on keeping the seat that Hukum Singh won with over 50 per cent of the vote share. The chief minister, his deputy and some of the top ministers have campaigned relentlessly.
On Sunday, Prime Minister Narendra Modi held a public meeting close to the Kairana constituency while inaugurating an expressway and spoke of issues concerning sugarcane farmers and law and order that the opposition alleges is a breach of the model code of conduct.
Bypoll to Palghar Lok Sabha seat in Maharashtra has added further tension to the already strained ties between the Shiv Sena and BJP. After the Shiv Sena gave a ticket to the son of Chintaman Vanaga - the sitting BJP lawmaker who died earlier this year -the BJP fielded former Congress minister Rajendra Gavit who joined the party earlier this month.
By-election to the reserved Bhandara-Gondiya seat is taking place after the sitting BJP parliamentarian Nana Patole resigned and joined the Congress. The BJP has fielded its former lawmaker Hemant Patle versus NCP's Madhukar Kukde who is also supported by the Congress.
For the Nagaland bypoll, it's a direct contest between two regional fronts, one each backed by the BJP and the Congress. The seat fell vacant after Neiphiu Rio resigned and became chief minister in alliance with the BJP. Mr Rio's earlier party, Naga People's Front, that is backed by the Congress has fielded former Chief Minister SC Jamir's son Apok Jamir.
By-elections will also be held for 10 assembly seats in nine states - Noorpur (Uttar Pradesh), Jokihat (Bihar), Tharali (Uttarakhand), Gomia and Silli (Jharkhand), Maheshtala (West Bengal), Ampati (Meghalaya), Palus Kadegaon (Maharashtra), Shahkot (Punjab) and Chengannur (Kerala).
In Bihar's Jokihat, the bypoll is being seen as a prestige battle for Chief Minister Nitish Kumar as sitting JD(U) lawmaker Sarfaraz Alam quit the party and joined the RJD after Mr Kumar joined hands with the BJP last year. After Mr Alam won the Araria Lok Sabha bypoll earlier this year, the RJD has fielded his younger brother Shahnawaz Alam to taken on JD(U)'s Murshid Alam.
The results for all the bypolls will be declared on Thursday.