As the ash cloud from Iceland's volcanic eruption continues to hover over the European skies, flights to and from Europe remained suspended.

The closing of European airspace has dealt a severe blow to the beleaguered airline industry. The crisis has cost the airlines at least $1 billion so far in lost revenue and could wipe out weaker carriers if it continues much longer, analysts say.

Scientists say that because the volcano is situated below a glacial ice cap, magma is being cooled quickly, causing explosions and plumes of grit that can be catastrophic to plane engines, depending on prevailing winds.

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Earth Hour has an impact across the World - In Pictures

First Pictures :Twin explosions hit Moscow subway ,37 Killed‎

In this image from a security camera bodies lie in the passageway of Lubyanka subway station in central Moscow after a bomb blast Monday March 29 2010.





At least 37 people have been killed after two female suicide bombers blew themselves up on Moscow Metro trains in the morning rush hour, officials say.

Twenty-four died in the first blast at 0756 (0356 GMT) as a train stood at the central Lubyanka station, beneath the offices of the FSB intelligence agency.

About 40 minutes later, a second explosion ripped through a train at Park Kultury, leaving another 13 dead.