Shanghai equities plunged seven per cent, leading an Asian meltdown, as more weak factory data fanned fears about the health of the world's second biggest economy.
In Europe, Frankfurt posted the heaviest losses, diving 4.3 per cent. Milan slumped 3.2 percent and Paris shed 2.5 per cent.
London stocks lost 2.4 per cent with China-exposed mining companies falling the heaviest.
Wall Street was also sharply lower in midday trading, with the Dow Jones Industrial Average down over two per cent.
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"Markets have been swept up in a renewed fear that China's economic slowdown is picking up speed after surprisingly weak manufacturing data," he added.
London's top fallers were mining giants Anglo American, which tanked 7.2 per cent, and Glencore which dropped 5.8 per cent, on demand fears in leading commodity consumer China.
Global markets were also spooked over the flare-up in tensions between Iran and Saudi Arabia, as investors returned to their desks after the Christmas and year-end holidays.
"On the first trading day of 2016, the markets have got off to a shocking start," added analyst Manoj Ladwa at brokerage TJM Partners.
"The problems in the Middle East have taken a turn for the worse with the Saudi-Iran stand-off. And China has only added to the negative sentiment as their economy shows further signs of slowing," he told AFP.
Authorities in China suspended trading on its stock markets in the early afternoon after shares collapsed.
The sharp losses revived memories of the summer rout that saw Shanghai crash about 40 per cent and trillions of dollars wiped off valuations.
Dealers began selling immediately after data from official and private surveys of manufacturing showed activity shrinking in December. The reports are the latest to highlight weakness in the economy, which is expected to have grown in 2015 at its slowest pace in a quarter of a century.