Photo taken on April 2, 2014 shows a bird's view of London city from ArcelorMittal Orbit Tower in the Queen Elizabeth Olympic Park in London, Britain. U.K.'s Department for Environment, Food and Rural Affairs issued warnings as high pollution levels were recorded on Tuesday. The pollution, a mix of local and European emissions and dust from the Sahara, is forecast in parts of south England, the Midlands and East Anglia. (Xinhua/Wang Lili)

Photo taken on April 2, 2014 shows a view of London city from ArcelorMittal Orbit Tower in the Queen Elizabeth Olympic Park in London, Britain. U.K.'s Department for Environment, Food and Rural Affairs issued warnings as high pollution levels were recorded on Tuesday. The pollution, a mix of local and European emissions and dust from the Sahara, is forecast in parts of south England, the Midlands and East Anglia. (Xinhua/Wang Lili)

Photo rotated 180 degrees taken on April 2, 2014 shows a reflection of the London city from ArcelorMittal Orbit Tower in the Queen Elizabeth Olympic Park in London, Britain. U.K.'s Department for Environment, Food and Rural Affairs issued warnings as high pollution levels were recorded on Tuesday. The pollution, a mix of local and European emissions and dust from the Sahara, is forecast in parts of south England, the Midlands and East Anglia. (Xinhua/Wang Lili)