Samajwadi Party candidate Sudhakar Singh has been fielded against BJP's Dara Singh Chauhan.
Voting for the Ghosi assembly by-poll will take place on Wednesday, setting the stage for the first electoral showdown between the BJP and an INDIA bloc constituent in Uttar Pradesh.
Formed recently, opposition Indian National Developmental Inclusive Alliance (INDIA) members such as the Congress, the CPI(M), the CPI and the RLD have extended support to Samajwadi Party (SP) candidate Sudhakar Singh, who has been fielded against BJP's Dara Singh Chauhan.
Mr Chauhan, the sitting MLA who crossed over to the saffron party from the SP and resigned from the seat, is seeking re-election and has the support of National Democratic Alliance (NDA) parties -- the Apna Dal (Sonelal), the NISHAD Party and the Suheldev Bharatiya Samaj Party (SBSP).
The bypoll, which was necessitated following Mr Chauhan's resignation, will have no bearing on the BJP government, which enjoys a comfortable majority in the 403-member state legislative assembly.
However, its outcome is important as it could be an indicator of what is in store for the 2024 elections to the 543-member Lok Sabha -- Uttar Pradesh sends 80 MPs to the Lower House of Parliament.
Of the nearly 4.38 lakh voters in Ghosi, 90,000 are Muslims, 60,000 Dalits and 77,000 from the "upper castes" -- 45,000 Bhumihars, 16,000 Rajputs and 6,000 Brahmins, according to estimates. Voting for the bypoll will be held from 7 am to 6 pm, and counting of votes will be held on September 8.
Besides the Congress and the Left parties, Singh also has the support of INDIA bloc members Aam Aadmi Party, the CPI(ML)-Liberation and the Suheldev Swabhiman Party (SSP) -- a splinter group of the SBSP.
Those who canvassed for Mr Chauhan included Uttar Pradesh Chief Minister Yogi Adityanath, Deputy Chief Ministers Keshav Prasad Maurya and Brajesh Pathak and leaders of BJP-led NDA members. SP chief Akhilesh Yadav and his uncle Shivpal Yadav were among the main campaigners for Singh.
In all, there are 10 candidates in the fray for the Ghosi assembly seat in Mau district. The Mayawati-led Bahujan Samaj Party (BSP) has not fielded any candidate for the bypoll for the constituency in the state's Puravanchal region (eastern Uttar Pradesh).
The bypoll will also be an opportunity for the ruling BJP dispensation to assert its hold in Uttar Pradesh. If the SP registers a win in Ghosi, it will strengthen Yadav's position and role within the opposition INDIA bloc, and also seal his candidature for leading the bloc in the state during the general elections.
On Sunday, Mr Yadav had appealed to voters in Ghosi to support his party's candidate and "teach the BJP, which purchases MLAs, a lesson".
In a post on the SP's handle on X, the party's chief had said the by-poll to the assembly segment is in discussion now because "the people of the country are affected by inflation, corruption and atrocities, caused by the BJP, I feel the people of Ghosi will defeat it".
While seeking support for Mr Chauhan, Chief Minister Adityanath had said only those who witnessed the 2005 Mau riots can understand the importance of Ghosi.
"At that time, the SP was in power and it could not do anything. Now, those who instigated the riots are seen begging for their lives in a wheelchair," he had said in an apparent reference to gangster-turned-politician Mukhtar Ansari, a five-time MLA from Mau.
On the support received from constituents of the INDIA alliance, Yadav had said such an election has hardly been seen in Uttar Pradesh, where "all boundaries from caste to religion were broken for an SP candidate".
During the campaign for the bypoll on August 20, a youth threw ink at Mr Chauhan -- a prominent OBC leader. The incident occurred when he was being welcomed by BJP supporters at Adri Chatti after attending a public meeting in Kopaganj block.
Mr Chauhan was a minister in the previous BJP government. He resigned on January 12 last year and joined the SP. The OBC leader resigned from the SP and returned to the BJP in July.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)