MUMBAI: Energy giant Reliance Industries chairman Mukesh Ambani has retained his title as the world's richest Indian - for the fifth year in a row - with a net worth of $21 billion, according to Forbes.

London-based steel baron L.N. Mittal follows Ambani as the country's second richest person, with wealth of $16 billion, the US business magazine said on its website Thursday ahead of its November Asian edition.

Despite holding the top position, Ambani has seen his fortune drop by $1.6 billion in the past 12 months, Forbes said.

“Reliance remains India's most valuable firm despite ongoing battles with federal oil ministry over KG-D6, country's largest offshore gas field where output has sharply declined,” said the report.

Mittal also had a tough year, losing $3 billion, “as shares of his ArcelorMittal, the world's largest steelmaker, tanked due to surging costs and slumping demand in Europe”, the magazine said.

Software firm Wipro's chairman Azim Premji is the third richest Indian with wealth of $12.3 billion.

The magazine noted that India's slowing economy got a recent boost when the government “ended months of policy paralysis” through a series of reforms to boost foreign investments in retail, insurance and aviation.

“The much-needed reforms perked up sentiments in what was otherwise another year of corruption scandals, this time in mining allocations,” Forbes said.

The data was compiled using shareholding and financial information obtained from the families and individuals, stock exchanges, analysts and India's regulatory agencies.