Updates paragraphs 3-6 to add market capitalisation, flows and a chart

By Bharath Rajeswaran and Shubham Batra

April 7 (Reuters) - India's stock benchmarks clocked their worst session in 10 months on Monday as a selloff fueled by U.S. tariffs intensified and investors dumped riskier assets on growing fears of a global recession.

The Nifty 50 .NSEI lost 3.24% to 22,161.1 and the BSE Sensex .BSESN fell 2.95% to 73,137.9. Both benchmarks posted their biggest single-day declines since June 4, 2024.

Since the U.S. tariff announcement on April 2, the total market value of all NSE-listed companies has fallen by $280 billion in three sessions.

"Indian markets are unable to quantify the uncertainty unleashed by tariff war," said Nilesh Shah, managing director at Kotak Mahindra Asset Management.

"The unfolding events will likely keep sellers on an aggressive sell mode and buyers on a reluctant buy mode."

Foreign institutional investors sold Indian shares worth $1.05 billion on Monday, the highest daily outflow since February 28. Meanwhile, domestic institutional investors bought $1.41 billion of shares.

Other global markets slumped, with the MSCI Asia ex-Japan index .MIAPJ0000PUS losing 8.3%. Japan's Nikkei 225 .N225 dropped 7.8%, while European stocks plunged with Germany's Dax .CDAX falling 5.3% and the British FTSE .FTSE shedding 4.1%.

President Donald Trump's new tariffs are "larger than expected" and are likely to impact inflation and growth, Federal Reserve Chair Jerome Powell said on Friday, flagging an uncertain outlook for the U.S. economy.

S&P 500 futures ESc1 slid nearly 5% in volatile trade on Monday, while Nasdaq futures NQc1 dived 5.7%, adding to last week's almost $6 trillion in U.S. equity market losses.

The Nifty volatility index .NIFVIX - or the fear index - rose 66% to 22.79, the biggest daily rise in 10 years. It touched the highest level since June 5, 2024.

While multiple brokerages such as Goldman Sachs and Bernstein expect the tariffs to hurt India's fiscal year 2026 GDP growth, government officials said on Monday they do not see any impact at the moment.

All 13 major sectors declined on the day.

IT companies .NIFTYIT, which earn a significant share of their revenue from the U.S., lost 2.5%.

With tariffs and trade wars, some of the discretionary spending in IT could get pushed out, triggering a fall in the sector, Shibani Kurian, senior fund manager and head of equity research at Kotak Mutual Fund, said on the Reuters Trading India chatroom.

Metals .NIFTYMET dropped 6.75%, while financials .NIFTYFIN shed 3.5%.

Private lenders HDFC Bank HDBK.NS, ICICI Bank ICBK.NS and oil-to-telecom conglomerate Reliance Industries RELI.NS - the three heaviest stocks that have a 32% weightage in the Nifty 50 - lost about 3.5% each.

The broader small-caps .NISMCP100 and mid-caps .NIFMDCP100 fell 3.9% and 3.6%, respectively, their worst session in nearly three months.

($1 = 85.8200 Indian rupees)

(Reporting by Bharath Rajeswaran in Bengaluru and Shubham Batra in New Delhi; Editing by Sonia Cheema and Devika Syamnath)

((bharath.rajeswaran@thomsonreuters.com; +91 9769003463;))