The purpose of the great wall of china, as originally constructed by the oin dynasty was to

to prevent invasion

Explanation:

it was made to keep people out

so the story tells of someone named kaushik choudhuri, but he does not narrate the story, a girl named hema does. hema tells the story in a second person point of view because you (the reader) are supposed to be the boy named kaushik.

here's an excerpt i found: "i was ushered into the fitting room, your mother watching approvingly as i took off my coat and sweater and tried on the bra."

source: