Snow covered mountains are seen from the waters of Unstad along the northern Atlantic Ocean on March 12, 2017, where the water temperatures is at five degrees centigrade and the air temperature is at minus two degrees centigrade. Unstad, the world' s most northern surf school, is perfect for those wanting to experience Arctic Surfing. (Photo by Olivier Morin/AFP Photo)

A woman covers her face as a fire burns in the middle of town during an anti-G20 protest on July 7, 2017 in Hamburg, Germany. Authorities are braced for large-scale and disruptive protests as Leaders of the G20 group of nations arrive in Hamburg for the July 7-8 G20 summit. (Photo by Leon Neal/Getty Images)

A reveller covered in paint takes part during the annual Cascamorras festival in Guadix, southern Spain September 9, 2015. The festival was inspired by a dispute between the town of Baza and Guadix over the possession of an icon of the Virgin of Piedad. The Cascamorras refers to representatives from Guadix, who were sent to Baza to recover the statue. As the Cascamorras had to stay perfectly clean to gain possession of the statue, Baza residents attempt to make them as “dirty” as possible. (Photo by Marcelo del Pozo/Reuters)

Vehicles pass through the heavy fog and air pollution that cover Skopje valley in the early morning, in Skopje, The Former Yugoslav Republic of Macedonia, 14 December 2017. According to media reports, Skopje is considered one of the most polluted cities in the world. (Photo by Georgi Licovski/EPA/EFE)

Igor Armicach, a doctoral student at Hebrew University's Arachnid Collection, looks onto giant spider webs, spun by long-jawed spiders (Tetragnatha), covering sections of the vegetation along the Soreq creek bank, near Jerusalem, Israel on November 7, 2017. (Photo by Ronen Zvulun/Reuters)

A woman wearing a scarf to cover her face looks on as she waits for a passenger bus on a smoggy morning in New Delhi, India, November 8, 2017. The Great Smog of Delhi is an ongoing severe air-pollution event in New Delhi and adjoining areas in the National Capital Territory of India, in November 2017. Air pollution at this time peaked on both PM 2.5 and PM 10 levels. It has been reported as one of the worst levels of air quality in Delhi since 1999. (Photo by Saumya Khandelwal/Reuters)

Chinese women run with a ball on a snow covered field in Shenyang in China's northeastern Liaoning province during International Women's Day on March 8, 2018. International Women's Day is celebrated on March 8 every year and commemorates the movement for women's rights. (Photo by AFP Photo/Stringer)

Students from St Andrews University are covered in foam as they take part in the traditional “Raisin Weekend” in the Lower College Lawn, at St Andrews in Scotland, Britain October 17, 2016. The weekend, which begins on Sunday, involves rituals for new students, culminating in a foam fight on Monday morning. (Photo by Russell Cheyne/Reuters)