The five Ws
Your primer to an issue in the news
Five ships were wrecked in a ferocious storm on Monday. One of the ships spilled up to 2,000 tonnes of oil. At least two other ships were carrying hazardous materials.
The oil spill happened in the Kerch Strait, a narrow passageway of water between Russia and Ukraine that links the Black and Azov Seas.
When will the spill be cleared up? The deputy head of Russia's environmental monitoring agency called it a 'serious environmental accident' and said, although emergency workers had started the clean-up almost immediately, it could take years to repair the damage.
Who has been affected? The bodies of three sailors have been recovered and another 20 are missing. Another 35 have been rescued.
Why are people so worried? The Kerch Strait is an environmentally sensitive area. It is an important migration route for birds and home to the Black Sea Porpoise. Tourists come to see the wildlife, so local people's livelihoods are also threatened.
How does the oil spill compare to other recent disasters? It is much smaller than that caused when a Liberian tanker sank off the coast of Spain in 2002. In that disaster 64,000 tonnes of fuel oil were spilled, damaging the coasts of Spain, France and Portugal.