I am south indian.why do hair falling occurs during chemotherapy?hair cells die?

Normal: That is normal and expected of anyone undergoing chemotherapy. Chemotherapy works by inhibiting cell division. Hair cells are one of the cells that divide fairly rapidly. So, they will be affected. The grow generally grows back after you complete your course of chemotherapy. This also the same reason you develop diarrhea, stomach upset, and change in taste.

Follicle matrix: Chemo affects the hair follicle matrix cells as it does with any other rapidly dividing cells in your body. If the effect is significant enough, the hair will separate from the bulb and fall. Sometimes the hair itself gets thinner and breaks at the base. This is a temporary effect most of the time soon it should grow back.