The figures published on Thursday were pulled together from sweeps conducted by the European Commission and national consumer authorities.

Of the 344 dubious claims made on company websites, 59% did not provide easily accessible evidence to back up claims. In 37% of cases, the claim made vague and general statements, such as “eco-friendly” and “sustainable”, giving the impression the product had no negative impact on the environment.

The European Commission said the misleading claims could potentially qualify as unfair commercial practices under EU rules.

“Greenwashing has increased as consumers increasingly seek to buy environmentally sound products,” justice commissioner Didier Reynders said. “I applaud companies that strive to produce eco-friendly products or services. However, there are also unscrupulous traders out there, who pull the wool over customers’ eyes with vague, false or exaggerated claims.”

The spread of the 344 sustainability claims examined by consumer protection cooperation authorities. Chart: European Commission.

The Competition Markets Authority (CMA) led and published a similar study on Thursday reporting almost identical findings. Assessing close to 500 sites, it found four in ten used tactics that could be considered misleading, such as using terms like “sustainable” and “natural products” without evidence, using own brand eco logos and hiding or omitting information such as a product’s pollution levels.

“Too many websites appear to be pushing misleading claims onto consumers, which means that companies offering products with a genuine environmental benefit are not getting the customers they deserve,” said the CMA’s Andrea Coscelli. “People should be able to easily choose between those companies who are doing the right thing for the environment and those who are not.”