I find this is a little irritating as the sins player. Players can move in and use the city action and do not even have to fight you. You can use the city action even in monsters are the district. It the red missions it can lea to a quick win for the hero players
Do what you can to dump tokens on there at the start of each round. If you are using corrupt nuns block the orbital strike action with a corruption token. Haven't played with the other acolytes yet, so maybe there are other powers to impede its usage. Enough fire in there, and along the route there and it will crisp players going to use it.