This is a novel by Salman Rushdie, "Haroun and the Seas of Stories", isn' t it?This is the first time I've ever seen(not read) his novel. It's very impressive.
It is fugurative and poetic, so those interpretations are not "correct", but
I hope I can help you to appreciate it.
A sad city means a city which makes people there sad, or where many sad people live.
Saddist of cities means a city which makes peple there very, very sad.
or the people living there are the saddest people in the world.
Ruinously sad means is like living in a ruin and feeling very sad.
it had forgotten its name is like an expression I came across when I read fairy stories as a child.The city is dishonored. People living there are looked down on.
They made people belch with melancholy even though the skies were blue.
The fish taste bad and are nutrient-poor, difficult to digest, so they fill people with gas and make them belch and feel melacholy, Even when it is beatiful weather,
Which never seemed to get enough of it
There are many sad things, and they are always increasing.
The depth of the city means an area which are very far form the edge.
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