This isn't proper English syntax. Yes, obviously we could come up with a situation in which to use this phrase, but the ordinary sounding "Чиє це місто?" translates to the ordinary sounding "Whose city is this?"
Чий is an adjective that means "whose." As such, it must agree with its noun in person, gender, and case. Чия is feminine, чиє is neuter, чий is masculine, and чиї is plural. It takes normal adjectival case endings in all other cases as well.