String bikini, latte drops. Photo provided to China Daily

As a result, clothing brands usually don't care how their textiles are made. Their primary concern, says Zhao, is that fabric quality is up to company standards.

Transparency is an issue that FINCH itself has encountered, with both Chinese- and foreign-owned suppliers.

"What chemicals are being used to treat the fabric from the beginning to the end of the process, it's always a little bit difficult to get complete transparency into that," Kaye says in a phone call from New York, where she is promoting the brand to more retailers.

"I think that dyes are so much better than they ever have been, and we do most of our prints digitally, so there's very little water, very little heat required to set them. But there's still petrochemical dyes, so there's still an impact."

When it comes to promoting more environmentally friendly fashion, advocates are definitely getting a hand from the beauty queen Xiang. At the next Miss Earth China competition in October, she wants to give her successor not only a crown but also a bikini. You can bet that part of the bathing suit was once upon a time, a plastic bottle.