BEIJING, Sept. 9 -- Prices of imported iron ore at 33 major Chinese ports have sunk to their lowest levels of the year, new data has showed.

In the week ending Sept. 9, the price index for iron ore imports with a 62-percent purity grade dropped five points from the previous week to 83. The index for imports with 58-percent purity dipped four points to 72, according to the Xinhua-China Iron Ore Index report released on Tuesday.

The report attributed the trend to steel firms' caution in making any purchase orders amid a sluggish steel market.

An economic slowdown and a cooling real estate market are depressing the steel market. Steel prices have slumped by 210 yuan (34 U.S. dollars) per tonne since the start of August to below 3,000 yuan per tonne, according to data from the Xiben New Line Stock Co., Ltd., a leading e-commerce service provider for resources including iron ore and steel.

The Xinhua-China Iron Ore Index, compiled through analysis of 33 sea ports, also showed that stockpiles of imported iron ore stood at 109.06 million tonnes as of Sept. 8, down 300,000 tonnes from a week ago.