The slum, or "zhopadpatti," is not only Lin's home for several months; it's also a source for some really great characters, its inhabitants. There's his pal Johnny Cigar, who helps Lin to see that you don't have to have a formal education or any money to think deep philosophical thoughts (though it helps if you have an ocean to stare at).
That's not to mention The Bear Handlers, who "seemed fantastic beings. Their bare arms and chests were well muscled beneath the blue paint, and their trousers were decorated with silver bells and discs and tassels of red and yellow silk. Both men had long hair, worn in dreadlocks as thick as two fingers, and tipped with coils of silver wire" (2.12.17). The exotic performers are just par for the course, adding to the exotic, distant vision Lin has of the slum.
The zhopadpatti's chai shop, run by Kumar, is an important meeting place for Lin and Prabaker, not least because the lovely Parvati works there. She and Prabaker later marry, just like her sister Sita and Johnny Cigar, all under the watchful eye of the girls' mother, Nandita. When she accompanies the four lovebirds as a chaperone, they call it a "triple date."
And who could hold the chaos of the slum together but the very wise Qasim Ali Hussein? He's the head man. He decides who gets to live in the slum, the rules, and how to enforce them. Lin's first vision of the man really says it all:
A man stood in the centre of the large arc of open space before the wall of flames, directing those who were fighting the fire as if he was a general ordering troops into battle. He was tall and lean, with silver-grey hair, and a short, pointed, silver-grey beard. He was dressed in a white shirt, white trousers, and sandals. There was a green scarf tied at his neck, and he held a short, brass-tipped wooden stick in his hand. (1.8.83)
The idea of fighting a fire as though you were fighting an enemy in battle reveals Qasim Ali's coolness, and his stylish duds reveal pride even in the face of poverty. He's also the one who comes up with the creative punishments Lin loves, such as forcing Faroukh and Raghuram to learn a prayer from each other's religious tradition after they insult each other's gods, or forcing the wife-beating Joseph to suffer a beating of his own, saving Maria's life.