The World's first diesel electric hybrid double decker bus parks in front of London's City Hall before it goes into service on route 141 in London on March 16, 2007 in London. Hybrid buses, which use a combination of diesel and electric power, are said to be central to the Mayor and Transport of London's plans for a cleaner, greener bus fleet in London, and aim to start cutting the capital's Carbon Dioxide emissions helping to tackle climate change.  (Photo by Matt Cardy/Getty Images)
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