The Advertising Standards Authority (ASA), an independent body created by the U.K.’s advertising industry to self-regulate the rules in the advertising codes, has discovered many companies are advertising unproven claims of environmental sustainability. Some of the companies under scrutiny are: Toyota, Lexus, easyJet and Volkswagen.

During September, the ASA received 93 complaints regarding environmentally-friendly claims in 40 different ads. The group created this checklist for advertisers to review before they make elaborate claims:

• Get your facts right. Don’t exaggerate the environmental benefits of your product: advertising claims should be backed up with documentary evidence.

• This is an area where scientific knowledge is developing all the time. Don’t present claims as being universally accepted if the science is inconclusive.

• Don’t use pseudo-science or terms that will not be generally understood by the readers of your ad.

• Avoid sweeping or absolute claims such as “environmentally friendly” or “wholly biodegradable”. It’s unlikely that you will be able to prove your product has no environmental impact.

• Saying something is “locally” produced should mean exactly that. Shipping goods in from abroad or the other end of the country doesn’t make them ‘locally sourced’.