Meaning of RAREFIED in English
If you talk about the ~ atmosphere of a place or institution, you are expressing your disapproval of it, because it has a special social or academic status that makes it very different from ordinary life.
It is important for the state’s future administrators to get out of the ~ air of the capital.
ADJ: usu ADJ n disapproval
Rarefied air is air that does not contain much oxygen, for example in mountain areas.
...living at very high altitudes where the atmosphere is ~.
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012