i think the answer would be - The longing for connection
The anecdote tells about the censorship of a book. In some countries of the world, government forces impose selection criteria on artistic and cultural production.
This episode is the fictionalization of a situation of repression that has happened repeatedly in history. In the famous book by Ray Bradbury "Fahrenheit 451" the burning of books is one of the central themes of the plot.
The fragment describes the situation of censorship and burning of a book that belongs to the narrator. Instantly produces the reader's empathy with this character whose work has been destroyed.
Answer: Big city that he lives in and he is afraid to let his cat outside
Explanation: Diego is someone who is living in a big city and it's normal for big cities that many dangerous situations that could happen to human or animals. In that city, there are many dogs that can harm his cat or people that can steal her and he is afraid because of those things and that is something that can best show why is he keeping Oz indoor.
He doesn't want his cat to be in dangerous situations because he doesn't want to lose his cat.