It is widely believed that China will soon impose import quotas on crude oil, just as it has done in the past with iron ore.

However, the same restrictions which the government has slapped on iron ore don't make sense with crude.

Today the world's three top producers account for over 70 percent of global iron ore output. For steel mills and other major iron ore buyers, there is still no alternative to this resource, meaning that suppliers can easily get away with upping their prices.

With crude oil though, things are different. There are actually several major crude oil producers contributing to global output. And crude oil, while vital to any modern economy, is becoming more replaceable as cleaner technologies emerge.

The market has much more of a say with crude prices than with iron ore, making it pointless for the Chinese government to intervene on imports.

The authors are Gao Yan and Wang Jilin, researchers from Beijing-based Unirule Institute of Economics.