I find it strange too that the conservative Garodia family would send their daughter alone to the underbelly of India, known as Bombay. I mean, it's not like the men are doing anything at home (aside from papad). Gauri could have gone or Menka.
It has to be because of the following:
She is going to go through a hard time in Bombay leading to the contest.
Karan there to help and support her, secretly of course.
Do you have any other ideas?