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View of the bed of Jacarei river dam, in Piracaia, during a drought affecting Sao Paulo state, Brazil on November 19, 2014. The Jacarei river dam is part of the Sao Paulo's Cantareira system of dams, which supplies water to 45% of the metropolitan region of Sao Paulo --20 million people-- and is now at historic low. AFP PHOTO / NELSON ALMEIDA (Photo credit should read NELSON ALMEIDA/AFP/Getty Images)

View of the bed of Jacarei river dam, in Piracaia, during a drought affecting Sao Paulo state, Brazil on November 19, 2014. The Jacarei river dam is part of the Sao Paulo's Cantareira system of dams, which supplies water to 45% of the metropolitan region of Sao Paulo --20 million people-- and is now at historic low. AFP PHOTO / NELSON ALMEIDA        (Photo credit should read NELSON ALMEIDA/AFP/Getty Images)