Clothes made of 100% polylactic acid fibre can decompose in a year, if buried in specific conditions, said Xtep.

These tops are 60% PLA and 40% polyester, creating a quick drying t-shirt.

A spokesperson for Xtep told sportstextiles.com: “The next step will be PLA and Tencel-blended products, as well as 100% PLA products, with the target of a 100% biodegradable sportswear garment.”

She added that the t-shirts offer natural antimicrobial properties, and while the cost is currently higher than a standard product, as the research advances and the technology scales, the price will come down.

In June last year, on World Environment Day, Xtep launched a PLA-containing jacket, after overcoming dyeing issues. It contained 19% PLA; today the company has made a version with 60% PLA.

Xtep said the PLA content of knitted sweaters on sale in the second quarter of next year will be increased to 67%, and in the third quarter, 100% PLA trench coats will be launched.

Xtep Group was founded in 1987 and listed in Hong Kong in 2008. In 2019, Xtep acquired the development, marketing and distribution of Saucony and Merrell in mainland China, Hong Kong and Macau, and wholly acquired the K-Swiss and Palladium brands. In 2020, Xtep Group's revenue exceeded 8.1 billion yuan (£890 million).