From big oil to big data - inside Indian tycoon Ambani's $20 billion start-up

By Promit Mukherjee MUMBAI (Reuters) - At the vast open-plan headquarters of Indian telecoms start-up Jio, billionaire oil tycoon Mukesh Ambani stands in short sleeves beneath a digital tracker that logs every new subscriber to his service. The 59-year-old is India's richest man, and his Reliance Industries oil & gas group is the country's most profitable. The ambitious Jio project could make Reliance the most comprehensive provider of telecom and internet services across India - and give it