How does the writer use language to create a negative impression of cairo in ‘american notes’ (part 2)?

In American notes, Dickens use these languages to create negative impression of Cairo : The trees were stunted in their growth, The banks were low and flat, the settlement and log cabins were fewer in number  . . .
Those languages give an image of a bad land that is not developed really well. hope this helps

Do you have any idea how to summarize it ? i'm willing to , but not do it for you.