Birla had engineered the merger of Idea Cellular, which was part of his Aditya Birla Group, and the India operations of Britain's Vodafone Plc in 2018 to form Vodafone Idea, creating what was the country's largest telecom operator at that time.

Birla, who has a net worth of $14 billion according to Forbes, will be replaced by Aditya Birla Group-nominee Himanshu Kapania as non-executive chairman, Vodafone Idea said https://bit.ly/2Vt3a65 in a stock exchange filing on Wednesday.

The company declined to comment on why Birla sought to step down, and representatives at the Aditya Birla Group did not immediately respond to an email from Reuters.

Vodafone has bled subscribers in recent years as it struggled to compete with Bharti Airtel and Mukesh Ambani-controlled Reliance Jio.

Compounding Vodafone's woes, the Indian government sought roughly $13 billion from the country's telecom operators in dues owed for the use of airwaves and as licence fees. Vodafone owed the majority share.

India's top court last year gave telecoms companies 10 years until 2031 to clear the dues after missing a January deadline. Last month, the court rejected a plea by the mobile carriers seeking corrections of what they called errors in the government's calculations of dues.

As of May 31, Vodafone had 277.6 million wireless subscribers, a distant third to rivals Reliance Jio and Bharti Airtel, with 431.2 million and 348.3 million, respectively, data from India's telecoms regulator showed.

Vodafone's shares were down 20.8% at 4.75 rupees as of 0439 GMT, and hit their lowest since May 15, 2020 at session low. Airtel's shares gained as much as 3.4%.

(Reporting by Anuron Kumar Mitra and Chris Thomas in Bengaluru; Editing by Sriraj Kalluvila)