A Congress leader said Mr Tandon is the sixth leader from the Scindia camp to rejoin the party.
Pramod Tandon, an associate of Union minister and BJP leader Jyotiraditya Scindia, on Saturday returned to the Congress's fold ahead of the assembly elections in Madhya Pradesh.
Mr Tandon, along with Ramkishore Shukla and Dinesh Malhar, was formally re-inducted into the Congress by the party's state unit chief Kamal Nath in Indore.
Mr Tandon had joined the Bharatiya Janata Party when Mr Scindia and several Congress MLAs close to him crossed over to the party in March 2020, toppling the Kamal Nath-led Congress government in the state in the process.
Mr Tandon was made a member of the state BJP's working committee, but he resigned recently.
He was said to be a die-hard loyalist of Jyotiraditya Scindia and his father, late Madhavrao Scindia, before him.
Samandar Patel, another BJP working committee member, had returned to the Congress along with hundreds of supporters on August 18 in Bhopal.
Mr Patel told PTI that Mr Tandon is the sixth leader from the Scindia camp to rejoin Congress. Baijnath Singh Yadav, another state BJP working committee member, had rejoined the Congress in July.
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