A woman wears a face mask in the part of the city near neighbourhoods known for burning coal for heating in Ulaanbaatar, Mongolia January 26, 2017. Not many people in Ulaanbaatar wear masks to protect themselves against pollution. (Photo by B. Rentsendorj/Reuters)

A illegal gold miner of Kamoro people, Tinus, pan for gold on February 4, 2017 in Timika, Papua Province, Indonesia. Indonesia produces over 70 billion dollars in gold a year and is home to the largest gold mine and the third largest copper mine in the world, the Grasberg mine, which is located at West Papua. (Photo by Ulet Ifansasti/Getty Images)

A young reveller participates in the annual Trinidad and Tobago Red Cross Society's Children's Carnival Competition at the Queen's Park Savannah in Port-Of-Spain, Trinidad and Tobago February 18, 2017. (Photo by Andrea De Silva/Reuters)

Campers set structures on fire in preparation of the Army Corp's 2pm deadline to leave the Oceti Sakowin protest camp on February 22, 2017 in Cannon Ball, North Dakota. Activists and protesters have occupied the Standing Rock Sioux reservation for months in opposotion to the completion of the Dakota Access Pipeline. (Photo by Stephen Yang/Getty Images)

In this Saturday, February 18, 2017 photo, revelers take part in the “Guanabara Pearl” carnival street party on Paqueta Island in Rio de Janeiro, Brazil. Merry makers ferried across Guanabara Bay to Paqueta Island for the parade. (Photo by Mauro Pimentel/AP Photo)

Rani rides home with her father on the back of his bicycle on March 6, 2017 in Khulna division, Bangladesh. Rani, who is now 16, was under pressure to marry a boy when she was 14-years-old despite the reluctance of Rani and her father, Abdul. (Photo by Allison Joyce/Getty Images)

Members of the Bavarian police and the Bundeswehr, the German armed forces, guard a vehicle checkpoint as they demonstrate a dynamic operation as part of the GETEX anti-terror exercises during a media event on March 9, 2017 in Murnau, Germany. (Photo by Philipp Guelland/Getty Images)

In this photo taken Wednesday, March 8, 2017, a hospitality staff member pose for photos near the shadow of a tall light pole near the Great Hall of the People where a plenary session of the National People's Congress is held in Beijing, China. (Photo by Ng Han Guan/AP Photo)