About 600,000 former herders have migrated to the Mongolian capital, Ulaanbaatar, over the past three decades as a result of the dzud, an extreme weather pattern in which an unusually cold winter follows an unusually dry summer. Dzuds are one of many reasons why people have been forced to migrate, however, and climate change, better education and economic and political change have also played a role. About 20 per cent of the country’s people have moved to Ulaanbaatar, doubling the city’s population (The Guardian, 5 January 2017). It is estimated that 40,000 people move there each year (Channel News Asia, 27 December 2017). In November 2016, national and two state agencies issued an emergency warning for a dzud (Save the Children, 20 December 2016). The phenomenon is expected to mainly affect northern areas of the country (IFRC, 17 December 2017). The mayor of Ulaanbaatar has banned people from moving to the city from the countryside until 2018 in a bid to improve air quality, which is among the worst in the world (Xinhua, 10 January 2017).