An old toilet is displayed during the “Toilet!? Human Waste and Earth's Future” exhibition at The National Museum of Emerging Science and Innovation – Miraikan on July 1, 2014 in Tokyo, Japan. The exhibition focuses on how the toilet has changed our daily lives and discovers what the most environment-friendly and ideal toilet is. (Photo by Keith Tsuji/Getty Images)

A Turkana boy herds cows as he carries a rifle in north western Kenya near the town of Kibish inside the Turkana region of the Ilemy Triangle September 26, 2014. The Turkana people have historically clashed over ethnic differences and precious resources such as fishing, pasture and fresh water with other tribes bordering their territory, such as the Dassanach from southern Ethiopia. (Photo by Goran Tomasevic/Reuters)

In this Sunday, March 2, 2014 photo, animal barber Mohamed Mahmoud shaves a customer's initials onto the rump of a donkey in Cairo, Egypt. Clients typically request for regular trims to keep animals cool in the summer, initials in English letters, and patterns – but sometimes they give Mahmoud full creative license. (Photo by Maya Alleruzzo/AP Photo)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

A Kenyan Red Cross personnel and a volunteer console a relative of a victim, at the site of a building collapse in Nairobi, Kenya, Saturday, April 30, 2016. A six-story residential building in a low income area of the Kenyan capital collapsed Friday night under heavy rain and flooding, killing at least seven people and injuring over 100 others, Kenyan officials said. (Photo by Sayyid Abdul Azim/AP Photo)

A bus goes through a flooded street in Wuhan, Hubei province, China July 6, 2016. (Photo by Reuters/China Daily)

A Hindu holy man or Sadhu walks back to his ashram after taking a dip at Sangam, confluence of Ganges river, Yamuna river and mythical Saraswati river in Allahabad, India, Thursday, August 4, 2016. (Photo by Rajesh Kumar Singh/AP Photo)

Indian devotees carry their luggage and wade through the flooded water in Varanasi, India, Friday, August 26, 2016. (Photo by Tsering Topgyal/AP Photo)