The offending advert included a picture of an oil refinery, with chimneys producing flowers and a headline that read "Don't throw anything away -- there is no away".

"What we can do is find creative ways to recycle," the advertisement said. "We use our waste CO2 to grow flowers, and our waste sulphur to make super-strong concrete."

The Friends of the Earth environmental campaign group complained to the ASA, arguing the claims misrepresented the facts and saying just 0.325 per cent of the company's carbon emissions were used to grow flowers.

Shell disputed this, estimating that 320,000 tonnes of carbon dioxide was due to be supplied to greenhouse growers this year.

"We believe that the ... advertisement (was) a creative and striking way of drawing attention to the problem of waste disposal," a Shell spokeswoman said in a statement.

In its ruling, the ASA upheld two of the three complaints, saying the advertisement breached "truthfulness" and "environmental claims".

The ASA said in the "absence of qualification", it found the claims were "most likely to be misleading".

Shell withdrew the advertisement in June and assured the ASA it would not be used again.