Iron ore fell to its lowest level of the year and copper plunged more than 6 per cent as Chinese investors led a wave of selling across industrial commodities markets amid concerns of a global economic slowdown.

The sharp falls came as the eurozone debt crisis entered a crucial week of negotiations. At the same time, however, investors are concerned by the possibility of a hard landing in China, which accounts for more than 40 per cent of demand for many industrial metals.

Those fears have been exacerbated by the sharp drop in spot iron ore prices. Benchmark Australian iron ore – with a 62 per cent iron content – delivered to China, which had been relatively stable amid the commodities sell-off over the past few months, fell to $145 a tonne, down 20 per cent from an early September peak of $183.