Swiss police officers stand beside of mock gates of the NEAT Gotthard Base Tunnel inside the event hall for the upcoming opening ceremony near the town of Erstfeld, Switzerland May 31, 2016. The celebrations of the opening of the Gotthard Base Tunnel will start on June 1, 2016. With a length of 57 km (35 miles) crossing the Alps, the Gotthard Base tunnel is the world's longest train tunnel. (Photo by Arnd Wiegmann/Reuters)

A young tiger tries to get at poultry parts hidden in a pumpkin at Magdeburg Zoo, Germany on October 30, 2025. The zoo is celebrating Halloween from October 31, 2025 to November 1, 2025. In addition to the puppet theater, children's carousel and children's train, visitors can carve their own pumpkins, which are then distributed to the zoo animals and serve as food. (Photo by Klaus-Dietmar Gabbert/Avalon)

Performers take part in a rain soaked Notting Hill Carnival on August 25th, 2014 in London, England. Despite the bad weather over 1 million visitors are expected to attend the two-day event which is the largest of its kind in Europe. The event has taken place on the West London streets every August Bank Holiday weekend since 1964. (Photo by Mary Turner/Getty Images)

A tourist walks inside the Ice Palace glacier hollow at Hintertux glacier, located at around 3250 meters above sea level, in Zillertal, Austria, 02 March, 2016. The hollow's temperature remains constant at 0 degrees Celsius, in summer and winter alike, and is also used by the University of Innsbruck for scientific research projects. (Photo by Lisi Niesner/EPA)

To mark World Water Day, on March 22nd Solidarités International and its agency BDDP Unlimited will roll out a campaign to build awareness of the scourge of undrinkable water.