What is the function of the passage of description of Bakha's family's outdoor kitchen?

This passage describes how Sohini has tried her best to keep up the kitchen, but she does not have the time, resources, or experience to do it well. It also describes how the kitchen lacks the four lines delineating its boundaries that are traditional in Hindu kitchens. These details serve to remind the reader of the burden that the mother's death presents to the family, especially Sohini. They also reiterate how impoverished the family is, and connect their desperate situation to a lack of interest in cleanliness.