Q: In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
Passage: After the Nazis came to power, he emigrated to Switzerland in 1933 and to the United States later. He began his studies in Zurich and worked part-time as a house teacher. Meanwhile, he wrote articles and book reviews for the Neue Zurcher Zeitung, using several pseudonyms because of prohibition of work. He earned his PhD and taught French and German Literature at various universities, including Princeton University and University of Wisconsin-Madison. During a journey to Europe, Vordtriede was surprised by the outbreak of the Second World War and interned as an Enemy alien in occupied France. By interventions, he became free months later and was allowed to go back to America. He met his mother in New York City late in 1941, who also emigrated to the USA. He received the American citizenship in 1946 and became a Guggenheim Fellow in 1957. His sister Franze emigrated in 1947 and went to Philadelphia.
Link Information: Zurich. The municipality has approximately 409,000 inhabitants, the urban agglomeration 1.315 million and the Zurich metropolitan area 1.83 million Answer: metropolitan area 1.83 million
A:
What is the population of the city where Vordtriede once studied and worked as a teacher?