shanghai financial district skyline at dusk

Financial markets were off to a rocky start on Monday, as a crash in China rekindled fears of slow global growth and tensions between Iran and Saudi Arabia continued to mount.

Global equities plummeted to the worst opening day to a new year in at least 30 years. The Dow Jones tumbled 400 points on the release of new data that showed a contraction in manufacturing. The S&P 500 fell 2.3%, after closing 2015 down 0.7%.

Inflation in Germany slowed unexpectedly, causing European equities to decline.

Emerging markets saw their biggest decline since August, as weak manufacturing data triggered a halt to trading in Shanghai.

Bonds soared, and the yen rallied as investors turned to haven assets.

Volatility indexes in Europe and the U.S. spiked, as the Europe Stoxx 50 soared 22% and the Chicago Board Options Volatility Index jumped 25%.

The Europe Stoxx 50 saw its worst start of the year ever, with 580 companies falling and the index losing 2.6%.

The MSCI Emerging Markets Index was down 3.5%, the biggest decline since August, as a major selloff in China was sparked by a devaluation of the yuan. The CSI 300 Index in China tumbled 7%, triggering a circuit-breaker than halted trade for the day.