Why does skin gets oily during summer and what to do to remove excess hair?

Increased: Increased temperature causes oil glands to make more oil. Excess hair can be removed by shaving, chemical depilatories, waxing etc.

Seasonal changes: Increased heat and humidity causes most skin-types to produce more oil. If your skin is oily to begin with, it is much more apparent in the summertime. Use an astringent twice daily, a light rather than heavy moisturizer, and try and keep cool and don't forget the sunscreen. Excess hair can be permanently removed by electrolysis though it is rather expensive. Other options - waxing, shaving.