Sitting on a restaurant terrace overlooking the Baltic Sea on a warm June evening in Sweden, what better drink than a green summer cocktail?

Perhaps followed by a delicious-looking Baltic farmer’s soup?

And you don’t even have to pay — you can scoop up such liquids for free from the most polluted parts of the Baltic Sea – also bordered by countries including Finland, Latvia, Russia, and Germany.

The images are part of a new campaign by the WWF environmental group to show off the problems of the Baltic – an almost enclosed sea that has suffered badly from pollution, including run-off from fertilisers that provoke big brief blooms of greenish algae that then die and sink to the bottom.

The WWF says that large areas of the Baltic seabed are “dead zones” starved of oxygen — and it says one study shows that 7 of the 10 largest such known zones in the world are in the Baltic Sea.

For years Baltic Sea countries managed to blame each other for pollution — the former Soviet Union spewed large amounts of toxic waste into the sea. But the end of the Cold War should be making cooperation easier.

The Baltic countries agreed a plan in late 2007 to clean up by 2021, including an innovative benchmark for “maximum allowable nutrient input” from nitrogen and phosphorus fertiliser polllutants.

Is there hope for a clean-up?

Or will Baltic soup still be green and unappetising in 2021?