China's exports of rare earths jumped to 31 per cent last month after the WTO ruled against export duties and quotas imposed by the communist giant.
According to the new customs data, Chinese companies exported 2,353 tonnes of rare earths last month, nearly 31 per cent more than the previous month.
China's rare earth exports fell to 1,556 tonnes in June, the lowest level of this year, according to the General Administration of Customs (GAC).
For the first eight months, exports rose 35 per cent year-on-year to 18,252 tonnes. However, in value terms, exports contracted 7.9 per cent from a year earlier to USD 261.6 million owing to falling prices, state-run Xinhua news agency reported.
Export till the end of last month was nearly 60 per cent of the full-year quota of 30,610 tonnes, shared by 28 production and circulation enterprises.
Last month the WTO ruled that China's export duties, quotas, and administration of rare earths, tungsten and molybdenum products were inconsistent with WTO rules and China's Accession Protocol.
The ruling followed petitions from the European Union, Japan and the United States challenging China's measures on exports of rare earths.
They alleged that the restriction had limited other countries' access to the minerals, given China a competitive advantage and hurt other producers and consumers.
Rare earths, a class of 17 mineral elements, are some of the most sought-after metals due to their vital role in green technologies like wind turbines and car batteries as well as in military sectors.
With its rare earth reserves accounting for 23 per cent of the global total, China supplies over 90 per cent of the world's market demand at the cost of great deal of pollution.
China says its measures were aimed at curbing environmental degradation and protect resources. It had set output ceilings, export quotas and stricter emission standards as well as high resource taxes for some ores.
In the previous two years, the companies had failed to use their full annual export quotas.
In 2013, China exported 22,493 tonnes of rare earths, up 38.3 per cent from 2012. But it was well below the full-year export quota of 31,001 tonnes.