Indonesian tourists take a selfie as Mount Bromo spews volcanic material and ash into the air during an eruption in Probolinggo, East Java, Indonesia, 31 December 2015. Indonesia's Mount Bromo is on the second highest alert level as its activity has increased in the last two months. (Photo by Fully Handoko/EPA)

This picture taken on March 1, 2016 shows a man running a mobile pig mating service and waiting outside a customer's home with his male pig in a cage pulled behind his motorcycle in the northern province of Bac Ninh. (Photo by Hoang Dinh Nam/AFP Photo)

A woman plays with a kitten inside of a line house in downtown Shanghai April 12, 2015. (Photo by Carlos Barria/Reuters)

A Sadhu or a Hindu holy man carrying his pet monkey walks after taking a dip at the confluence of the river Ganges and the Bay of Bengal on the occasion of “Makar Sankranti” festival at Sagar Island, south of Kolkata, India, January 14, 2017. (Photo by Rupak De Chowdhuri/Reuters)

A walker has left a handprint on a snow- covered tree trunk on Grosser Feldberg mountain in the Taunus mountain range, Germany, 16 January 2017. (Photo by Frank Rumpenhorst/DPA)

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 general view of atmosphere at the annual VOLT Festival in Sopron, 208 kms west of Budapest, Hungary on August 16, 2016. (Photo by Rockstar Photographers)

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