The Congress party suffered another setback in Madhya Pradesh a week before the bypolls when its MLA Rahul Singh resigned from the state assembly. Hours later, Mr Singh joined the Bharatiya Janata Party in the presence of Madhya Pradesh Chief Minister Shivraj Singh Chouhan in Bhopal.
He is the fourth Congress MLA to have joined the BJP since July.
Rahul Singh, a legislator from Damoh, gave his resignation to acting Speaker Rameshwar Sharma, who accepted it. "MLA from Damoh area, Rahul Singh has resigned from his post which has been accepted," Mr Shama tweeted.
"I have worked with the Congress for around 14 months but I couldn't work for development. All the public welfare schemes in Damoh have been put on hold. Today, I have joined BJP willingly. I am sure that Damoh will rise to touch great heights," Mr Singh said.
Welcoming Mr Singh to the fold, Chief Minister Chouhan said, "After losing hope in Congress, those who want to work for development are leaving that party. Today, Rahul Singh Lodhi has joined the BJP after resigning as the Damoh legislator."
With this, the Damoh seat has been declared vacant. However, the Election Commission is yet to decide if the by-election for this seat will also be held on November 3 when 28 other seats go to polls.
The BJP at present has 107 MLAs and it needs to win just nine more seats to reach the magic figure of 116 - the simple majority mark in the 230-member House. The Congress's strength in the House has now been reduced to 87.
The Congress will need to win all the 28 seats where by-polls are due and Damoh to wrest power from the BJP.
By-elections were necessitated after 22 rebel Congress MLAs, loyalists of former Union minister Jyotiraditya Scindia, resigned from the party in March this year leading to the fall of the 15-month-old Kamal Nath government in Madhya Pradesh.