The race between India’s two top billionaires, Gautam Adani and Reliance Industries’ Mukesh Ambani, to become the richest Asian has confounded observers.

While Mukesh Ambani leads most of the time, the Adani Group chairman became the only Indian among the world’s top 10 richest men on April 4.

The Adani Group is India’s largest closely-held thermal coal producer and coal trader. It is also the country’s largest port operator. As of March 31, the conglomerate reported total revenue of $5.3 billion.

Adani’s wealth has been growing steadily. Following a debut on the world’s centibillionaires’ list on April 2, his total net has increased to $105 billion, compared to Ambani’s $100 billion, according to Bloomberg Billionaires Index.

Only two weeks ago, Ambani was Asia’s richest man with $103 billion in wealth.

Adani’s rise

The 59-year-old Adani’s rise has been spectacular – the past decade saw a 1,830% rise in his wealth, according to the 2022 M3M Hurun Global Rich List. The Reliance Industries chief’s wealth increased 400% in this period.

Adani added $49 billion to his wealth in 2021, Hurun research shows. This is an addition of 6,000 crore rupees ($791 million) every week of the year. The cumulative addition to his wealth in 2021 has been more than that of the world’s top three billionaires Elon Musk, Jeff Bezos and Bernard Arnault.

Ambani versus Adani

This direct clash was first highlighted in 2021 when Ambani announced the entry of his oil-to-telecom conglomerate into green energy.

A fossil fuel giant, Reliance Industries’ then announced a Rs 75,000 crore renewable energy investment plan. If this succeeds, it would make it responsible for meeting a fifth of India’s 2030 green energy target of 450 gigawatts.

The Adani Group, meanwhile, plans to invest $70 billion over the next decade across renewable energy generation, component manufacturing, transmission and distribution. The group is already the world’s largest solar power developer.

This article first appeared on Quartz.