An Egyptian farmer holds soil to show the effects of a drought on a farm formerly irrigated by the Nile River, in Al-Dakahlya, about 75 miles from Cairo, on June 4. Egyptians are concerned that Ethiopia's ambitious hydroelectric dam project on the Nile will impact downstream neighbors.

A polluted stream which has turned white in Dongchuan district of Kunming, Yunnan province, March 20. According to local media, the source of the pollution is waste water discharged by nearby mining industries.

Farmers dig ditches from a white polluted stream to farm fields for irrigation in Dongchuan district of Kunming, Yunnan province, March 21.

A villager carries buckets of water to be used for drinking from a white polluted stream in Dongchuan district of Kunming, Yunnan province, March 20.

A villager holds two bottles of water, one from the polluted stream, left, and the other normal mineral water, in Dongchuan district of Kunming, Yunnan province, March 21.

Workers put together a pipeline during the construction of the Olmos Irrigation Project in Peru's northwestern region of Lambayeque, March 15, 2013.

Section of pipe are stockpiled in Peru's northwestern region of Lambayeque.

A Chinese winter swimmer washes himself after finishing a swim in the freezing waters of the Song Hua River in Harbin City, Heilongjiang province, northeastern China, on Dec. 17. More than 500 winter swimmer belonging to a local winter swimming association are carrying out their winter swimming exercise everyday while the outside temperature is about minus four degrees Fahrenheit. The swimmers believe the exercise is good for their health.

Chinese winter swimmer prepare to swim in the freezing waters of the Song Hua River in Harbin City, Heilongjiang province, northeastern China, on Dec. 17.

A Chinese man swims in the freezing waters of the Song Hua River in Harbin City, Heilongjiang province, northeastern China, on Dec. 17.

Chinese winter swimmer Gong Shulin finishes a swim in the freezing waters of the Song Hua River in Harbin city, Heilongjiang province, northeastern China, on Dec. 17.

Members of the public experience the 'Rain Room' art installation by 'Random International' in The Curve at the Barbican Centre on Oct. 3, 2012 in London, England.

A man checks his phone as he experiences the 'Rain Room' art installation by 'Random International' in The Curve at the Barbican Centre on Oct. 3, in London, England.

Susan Gell and Roy Rodgers exercise their horse, Shoshoni, in Loch Lomond on Sept. 19 in Luss, Scotland.

Susan Gell and Roy Rodgers exercise their horse, Shoshoni, in Loch Lomond on Sept. 19 in Luss, Scotland.

A boy swims in water collected from a stone spout near Bangalamukhi temple in Katmandu, Nepal, Tuesday, Aug. 28. There are dozens of centuries-old stone spouts that are still used to collect household water or as public bathing areas in the city.

A boy reacts as his sister splashes water from a stone spout near Bangalamukhi temple in Katmandu, Nepal, Tuesday, Aug. 28.

A boy bathes in water from a stone spout near Bangalamukhi temple in Katmandu, Nepal, Tuesday, Aug. 28.

Residents run towards a government tanker delivering drinking water in New Delhi, India on July 6, 2012.

Residents crowd around a government water tanker in New Delhi on July 6, 2012.

A woman holds her child and joins a crowd around a government tanker delivering drinking water in New Delhi on July 12, 2012.

Residents crowd around a tanker in New Delhi on July 6, 2012.

A man sucks on a hose to pull water as a crowd gathers around a tanker in New Delhi on July 13, 2012.

A woman carries buckets filled with water from a tanker in New Delhi on July 6, 2012.