IF THE best-known emblem of Mongolia is its mighty 13th-century conqueror, Genghis Khan, the second-best-known is probably the humble nomadic dwelling known as a yurt. Legend has it that Genghis Khan himself ruled his vast empire from—suitably enough—an especially large one, nine metres in diameter. The Mongolian word for yurt, ger, has come to mean “home” and it also forms the root of the verb “to marry”. Why, then, does this central and beloved bit of cultural patrimony seem to be going out of style?

With their collapsible lattice frames made of wood and their highly efficient felt insulation, yurts are both warm and transportable. Indeed, many nomads have transported their yurts to the edges of the capital, Ulaanbaatar. On three sides of the city ramshackle neighbourhoods are populated by migrants from all across Mongolia’s vast countryside. These steadily growing hillside areas are universally referred to as “ger districts”, and those white domes are their most prominent feature when viewed from the heart of the city. But fewer than half of the residents in these districts actually live in yurts. Most have taken the 700 square metres of land alloted to them by national law and built simple fixed structures of wood, brick or concrete.

The ability of rural dwellers to migrate to cities increased suddenly with Mongolia’s transition, in 1990, from a Soviet-imposed communist system to democracy. Since 2000 the influx of herders to Ulaanbaatar, by far the country’s largest city, has grown especially fast. Drought, together with an increased frequency of the phenomenon known in Mongolian as a dzud (an especially dry summer followed by an especially harsh winter that livestock cannot survive) have made herding more difficult. At the same time, Ulaanbaatar’s rapid development has made it more attractive as a source of both job opportunities and services, including health care and education. But city officials have so far failed to provide basic infrastructure to the growing ger districts. The pit latrines that serve well enough for yurt dwellers in sparsely populated rural areas are ill-suited to the densely packed settlements on Ulaanbaatar’s edges. Neither are the ger districts connected to city heating systems, forcing residents to burn coal for their cooking and heating needs. This generates horrendous pollution, and a good deal of grumbling among residents of the city’s built-up areas.

Add to this is the fact that once they give up herding for city life, migrants have less use for one of the yurt’s main advantages: portability. All this explains the results of a survey of Ulaanbaatar’s ger-district residents, published in 2015: 72% of respondents said they would move into an apartment if they could. And even in the countryside Mongolians are heeding the siren song of modern living and being lured out of their yurts, albeit at a slower rate. Between 2010 and 2015, the proportion of households living in yurts declined by 1.3 percentage points, according to Mongolia’s national statistics bureau. It will take some time, but the noble yurt looks like it is on its way to joining Genghis Khan as a bygone symbol of Mongolia’s proud past.