Ashok Lavasa, who was next in line to head the poll panel, on Tuesday resigned as Election Commissioner and would soon be joining the Asian Development Bank as vice president, sources said.
Lavasa, the sources said, has sent his resignation to Rashtrapati Bhavan and has requested to be relieved on August 31.
He would be joining the Philippines-based ADB sometime in September, they added.
He was named the bank's vice president last month.
"The ADB has appointed Ashok Lavasa as Vice-President for Private Sector Operations and Public-Private Partnerships," the multilateral lending agency had said in a statement last month. "He will succeed Diwakar Gupta, whose term will end on August 31."
Lavasa, who would have retired in October 2022 had he become the Chief Election Commissioner, is the second election commissioner to step down from the poll panel before the completion of his term.
The last time an election commission put in his papers was in 1973 when CEC Nagendra Singh was appointed a judge in the International Court of Justice at The Hague.
His resignation comes at a time when the Election Commission is preparing to hold Bihar assembly polls amid the coronavirus pandemic.
Lavasa, a career bureaucrat, joined as Election Commissioner on January 23, 2018, and being senior most on the poll panel would have become CEC in April next year after the term of incumbent Sunil Arora ends.
Lavasa still has over two years left in his term at the Election Commission of India and as CEC, he would have conducted assembly elections in Uttar Pradesh, West Bengal, Uttarakhand, Punjab, Manipur, and Goa, among other states.
His premature exit puts his colleague Sushil Chandra next in the line of succession.
According to the provisions of the Election Commission (Conditions of Service of Election Commissioners and Transaction of Business) Act, 1991, an EC or the CEC can tender his or her resignation addressed to the President.
Lavasa had made headlines during the 2019 Lok Sabha elections when he gave a dissenting note to the Election Commission of India giving a clean chit to Prime Minister Narendra Modi and former Bharatiya Janata Party president Amit Shah on allegations of violating the Model Code of Conduct.
Three members of the Lavasa family including his wife had come under the scanner of the income tax department for alleged non-declaration of income and disproportionate assets.
The family members had denied the allegations.
An MBA degree holder from Southern Cross University in Australia, and MPhil in Defence and Strategic Studies degree from the University of Madras, Lavasa, a 1980 batch IAS officer of Haryana cadre, also worked as finance secretary.