Mahajan, a three-time Congress MLA and former minister, had resigned from the party in September 2022 ahead of the assembly polls and joined the BJP.
The Congress has a clear majority with 40 out of the 68 MLAs and the support of three independent MLAs.
Despite the fact that the BJP, with 25 MLAs, is far behind in the number game, it has forced a contest by fielding Mahajan against Singhvi.
The Congress had issued a whip to its MLAs to vote for Singhvi following which the BJP had accused the ruling Congress of issuing whip to their members to pressurise them and maintained that the MLAs have been elected democratically and have the right to vote as per their wish.
The BJP candidate has sent a complaint to the chief election commissioner drawing his attention to the three line whip issued by the Congress to vote for the party candidate.
In his complaint, Mahajan said that such a whip is not only unethical but also against the conducting of elections to the Rajya Sabha as it will affect the decision making ability of the MLAs.