Traditional miners carry sulphur on the Ijen volcano complex on May 25, 2009 outside Banyuwangi, East Java, Indonesia. Miners carry the solidified yellow sulphur blocks from the crater floor to the rim for as many hours a day as they can tolerate, paid by the kilogram of sulphur they extract. The average wage is USD $.05 per kilogram of sulphur and a worker, depending on his strength and stamina, carry on average 3 baskets of 70-80kg per day, earning him around USD $11. (Photo by Ulet Ifansasti/Getty Images)

A woman prays at the edge of a river during a protest against the building of a pipeline near the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S. November 2, 2016. (Photo by Stephanie Keith/Reuters)

People spray water in the street ahead of “Songkran”, the annual Thai New Year water-throwing festival, in Kowloon City, Hong Kong, China, 09 April 2017. The pouring of water is a key element in the festival as it represents purification and the washing away of one's sins and bad luck for the year. The event also includes a “Miss Songkran” pageant where contestants are clothed in traditional Thai dress, and a winner is crowned. This year's “Songkran” will begin in Thailand on 13 April 2017. (Photo by Alex Hofford/EPA)

A mine worker is seen outside “The Progreso” gold mine near La Paz, November 13, 2014. According to local media, the president of the Central Bank of Bolivia (BCB) Marcelo Zabalaga said on Thursday that the falling price of oil and minerals in the international market will not affect the national economy. (Photo by David Mercado/Reuters)

A German contestant adjusts his helmet during the “Battle of Nations” in Aigues-Mortes, southern France, Friday, May 10, 2013 where Middle Ages fans attend the historical medieval battle competition. The championship will be attended by 22 national teams, which is twice the number it was last year. The battle lasts until May 12. (Photo by Philippe Farjon/AP Photo)

A visitor stands in the exhibition “I Am A Drop In The Ocean” dedicated to the artistic and visual expressions of the protests that shook the Ukraine from November 2013 until February 2014 at the Kuenstlerhaus gallery in Vienna, Austria, Thursday, April 10, 2014. The exhibition opens its doors from April 11 until May 23, 2014. (Photo by Ronald Zak/AP Photo)

Some 300 girls and women in India still practise open defecation. Over half the country’s population, 800 million people, do not have access to a toilet that meets basic standards. (Photo by Poulomi Basu/WaterAid)

The Tsaatan people are one of the world’s last groups of nomadic reindeer herders and they live in Khövsgöl Aimag in northern Mongolia. They are originally from across the border in what is now the Tuva republic of Russia. (Photo by Pascal Mannaerts/Rex Feature/Shutterstock)