Premise: Datong () is a prefecture-level city in northern Shanxi province, People's Republic of China, located in a basin at an elevation of 1040 m and bordering Inner Mongolia to the north and west and Hebei to the east. It had a population of 3,318,057 at the 2010 census of whom 1,629,035 lived in the built up area made of 3 out of 4 urban districts, namely Chengqu, Kuangqu and Nanjiao District.
Hypothesis: The population of Datong exploded during the 1990's to reach its current level of 3,318,057.