LONDON - APRIL 20: Air pollution hangs over the heart of London in this view of the BT Tower looking towards the city on April 20, 2007 in London, England. (Photo by Mike Hewitt/Getty Images)
LONDON - APRIL 20: Air pollution hangs over the heart of London in this view of the BT Tower looking towards the city on April 20, 2007 in London, England. (Photo by Mike Hewitt/Getty Images)