The UK’s Competition and Markets Authority (CMA) announced the release of a new compliance guide for fashion brands and retailers, aimed at helping the companies to comply with the regulator’s Green Claims Code when making environmental claims about their products and services.

Alongside the launch of the new guide, the CMA announced that it has sent letters to 17 “well-known fashion brands,” advising them to review their business practices. According to the CMA, the letters highlight several areas of concern regarding the companies’ green claims, including the use of broad or general terms, and whether certain products are being wrongly included in ‘eco’ ranges.

The announcements arise after the CMA launched an investigation into green claims in the fashion industry in 2022. The investigation was prompted by the industry’s concerns, which were discovered during a broader probe into greenwashing, or whether consumers are being misled by sustainability claims made in product and service marketing. Concerns brought up by the CMA’s sector analysis included statements made by businesses about the environmental sustainability of their goods—like the use of recycled materials—without offering proof to support their assertions or identifying the specific items they relate to.

The CMA stressed in the recent letters to the fashion labels that they must make sure their promises are truthful and do not deceive customers since it will soon have the authority to sanction corporations up to 10% of their global revenue if they violate consumer law.

The new guide’s main points are as follows: fashion brands should make sure that the standards used to include products in green collections are explicit and include any minimum requirements; they should be transparent when searching for green products using filters or other navigational tools; and they should clarify whether or not green claims apply only to certain aspects of a product’s lifecycle.