Nongfu Spring, one of China's biggest bottled water companies, recently filed a lawsuit against The Beijing Times over reports that its products fail to meet national standards.

In an online statement on May 6, the company said it is seeking 60 million yuan ($9.7 million) in damages from the paper, which it accuses of defamation.

The dispute first erupted on April 10 when The Beijing Times published a report that said Nongfu Spring, whose sales of bottled water account for 20 percent of the domestic market, did not meet the national water quality standard, and instead adhered to a lower standard set by Zhejiang Province where the company is based.

Bottled-water companies in China adopt a variety of water standards, including national standards set by different ministries, standards by local governments and those made by the companies themselves.

Experts say a lack of a unified standard regulating bottled water not only brings confusion but makes it difficult to supervise companies.