Polish-German relations. Or the smell of dead fish

Background

The mysterious deaths of hundreds of tonnes of fish in the Oder - the river that separates Germany and Poland - is not just an ecological disaster, it also exposes just how frayed relations between Berlin and Warsaw are.

So far, some 200 tonnes of dead fish have been pulled out of the river's waters. Poland has deployed over 6,000 emergency service personnel to deal with the disaster.