It is the most populous city in Northwest China , as well as one of the three most populous cities in Western China .
As of 2018 Xi'an has a population of 12,005,600 , and the Xi'an - Xianyang metropolitan area has a population of 12.9 million .
Xi'an is the most populous city in Northwest China , as well as one of the three most populous cities in Western China .
As of 2018 Xi'an has a population of 12,005,600 , and the Xi'an - Xianyang metropolitan area has a population of 12.9 million .