Commercial aviation autoland was initially developed in the United Kingdom, as a result of the frequent occurrence of very low visibility conditions in winter in North-west Europe. These occur particularly when anticyclones are in place over central Europe in November/December/January when temperatures are low, and radiation fog easily forms in relatively stable air. The severity of this type of fog was exacerbated in the late 1940s and 1950s by the prevalence of carbon and other smoke particles in the air from coal burning heating and power generation.