Telenor Norway said it has used its big data operations to look at movements and travel over the Christmas holiday, based on signals received by its base stations in different boroughs. Telenor Research data scientist Gro Nilsen said more than a quarter of Oslo residents left the capital over the festive period, with many heading for the hills, and others travelling abroad to foreign countries. On 25 and 26 December, there was a 26 percent drop in mobile signals registered in Oslo, and from 28 December to 01 January, over 20 percent of people had left its Baerum suburb.