Singapore/New Delhi, Mukesh Ambani remains at No. 1 for the 13th year in the Forbes List of Indias 100 Richest, as the tycoon added $37.3 billion, bringing his fortune to $88.7 billion, a rise of 73 per cent.

Amid the Covid-19 pandemic which hit India hard and led to a sharp economic contraction, half of the nation's 100 richest on the 2020 Forbes India Rich List saw gains. Their collective net worth rose 14 per cent to $517.5 billion from a year earlier, even as the benchmark BSE Sensex stock index remained flat from a year ago.

Mukesh Ambani accounted for more than half of those gains.

Shares of his Reliance Industries soared when, amid the nation's lockdown, Ambani raised more than $20 billion from a string of marquee investors for Jio Platforms, Reliance's fast-growing digital arm. Investors are now eyeing Reliance Retail, which has already raised more than $5 billion.

Infrastructure magnate Gautam Adani retains the second spot on the list by boosting his net worth 61 per cent to $25.2 billion. Forbes said unfazed by the pandemic-induced travel slowdown, Adani, who aspires to be India's airport king, acquired a 74 per cent stake in Mumbai airport, the country's second-busiest.

Tech tycoon Shiv Nadar, who ceded the post of chairman of HCL Technologies in July to his daughter Roshni Nadar Malhotra, jumps three places to No. 3 with $20.4 billion as shares of India's third-largest tech firm surged.

Radhakishan Damani of Avenue Supermarts climbs three spots to No. 4 with a net worth of $15.4 billion. The Hinduja brothers with $12.8 billion, round out the top five.

With a global health crisis raging, pharma entrepreneurs fared well. The fortune of vaccine billionaire Cyrus Poonawalla (No. 6), whose privately held Serum Institute of India—led by his son Adar—has joined the race to produce Covid-19 vaccines, was up 26 per cent to $11.5 billion.

Listed companies making drugs to treat the virus saw their shares jump. The biggest percentage gainer on the list was Kiran Mazumdar-Shaw (No. 27), founder of Biocon, which is set to start phase 4 trials of a potential Covid-19 drug. Her wealth nearly doubled to $4.6 billion.

The Covid-19 pandemic benefited fortunes in some other sectors as well. Increased data consumption by those stuck at home during the pandemic lifted telecom company Bharti Airtel's share price by 42 per cent in the past year and boosted the wealth of chairman Sunil Mittal and his family. He climbs three spots to No. 11 with a fortune of $10.2 billion.

The net worth of M.G. George Muthoot (No. 26, $4.8 billion), chairman of lending firm Muthoot Finance, also rose as the demand for gold-backed loans surged amid a pandemic-induced cash crunch.

Naazneen Karmali, Asia Wealth Editor and India Editor of Forbes Asia, said: "Despite the double whammy of a plunging economy and a rising pandemic, India's 100 richest managed to increase their combined wealth this year. The new faces on the list are further proof that the Indian entrepreneurial DNA has the will to surmount the odds."

More than a third of the listees saw their wealth decline, notably those with interests in real estate. A dozen dropped off the list, including Future Group founder Kishore Biyani, who sold the bulk of his debt-laden retail empire to Ambani's Reliance Retail.

The minimum amount required to make this year's list was $1.33 billion, down from $1.4 billion last year.