After 50 years of building businesses, Sunil Bharti Mittal expects Airtel to be debt-free by 2029. With the balance sheet getting stronger, could share buybacks be the telecom giant's next big move? Mittal also discusses AI, data centres and the next phase of growth. Sunil Bharti Mittal raised $18 billion in 34 months to save Airtel amid Indian telecom disruption.