According to the textbook, of all the cities where Paul ministered, perhaps the had more evidence of Satanic activity and demonic oppression than any other place.

Ephesians

Explanation:

Although you did not present the textbook to which the question refers, it is possible to say that the city of Ephesians was the city in which the Apostle Paul felt a great satanic activity and demonic oppression. It is likely that Paul has this perception of the city because of the numerous pagan activities that existed in the place and because of the large temples to random deities that were not consistent with the Christian faith.