What is the point of the controversial last scene? What are some places in the novel Roy examines the concept of beauty in a broken world?
In many ways you answered the first question with the second. The last scene between Ammu and Velutha is quite poignant and quite graphic. Roy spares no detail in describing the physical love that takes between Ammu and Velutha, the untouchable. But she describes this love in a beautiful way. The two are physically attracted to each other, they genuinely love each other, and for the time that they are together, they experience ecstasy. If they did not live in a world with love laws that forbade this type of relationship from taking place, Roy makes it clear that this beautiful relationship would have brought joy to each of them as well as to the twins who adored both Ammu and Velutha. But because they live in a society that still honors the caste system, their love is doomed. The novel ends with "Tomorrow," a particularly poignant word, since the readers already know what the future holds: Velutha's horrid death, Ammu's being cast out of the house, the Pickle Factory closing, Estha being returned to his father, and Rahel becoming distant and contemptuous of her mother.
Other instances of beauty in a broken world might include Velutha playing with the children, allowing them to paint his fingernails; Chacko's roses that he holds "fatly, fondly"; and Estha's singing during the Sound of Music.