Can you have a token in a city with a busted disk? I saw a rule stating that when moving a busted disk to a new city, any token there is repressed.
I assume therefore that any city with a disk can never host a token. And likewise, when a city loses its disk it can.
B5 says: "Any Emporium covered by a disk is not in play, does not generate Levies, and cannot have Agents played in it. Any Tokens on an Emporium that becomes covered by a disk (due to a trade shift) are immediately Repressed."
"An Emporium (B5) is not in play and can hold no Tokens until and unless the disk covering it is moved to another Emporium through a trade shift one-shot (H1)."