Europe controls half of its carbon emissions through the Emissions Trading System (ETS). It's one of the world's biggest policies aimed at promoting a low-carbon, clean energy future. Unfortunately, the sensible principle of having tradable pollution allowances (EUAs) has been undermined - some of Europe's biggest polluters have been handed millions more allowances than they need - for free.

Use our map to discover the Carbon Fat Cats - the companies making lots of money (and not many carbon savings) through Europe's flagship climate policy.