Dr Hondou examined mobile-phone usage in enclosed spaces such as railway carriages, buses and lifts, all of which are, in essence, metal boxes.

ECONOMIST: Are mobiles phones on trains dangerous or not?

And Bulgaria, which found it hard to enforce a partial ban, hopes to achieve a complete prohibition on smoking in enclosed spaces by mid-2012.

ECONOMIST: The law may sometimes save an ass

The home gets its name from the flower-shaped roof which acts as a giant leaf that shields the enclosed spaces from the scorching sun.

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Smoking in enclosed public spaces such as hospital premises has been banned in Scotland since 2006.

BBC: NHS board bans smoking in grounds

Scotland prohibited smoking in enclosed public spaces in 2006 and the rest of the UK followed the year after.

BBC: New York's outdoor smoking ban: Will the world follow?

In 2006, MPs voted by a huge margin to ban smoking from most enclosed public spaces in England, including pubs, clubs and offices.

BBC: Nick Clegg: I've given up 'the ciggies'

In 2011, China banned smoking in restaurants, bars, and in several other enclosed public spaces, though it is still legal to smoke in offices.

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