Q: My question is regarding skin colour. My skin is fair but when I used to visit some hill stations like Mussoorie or Nainital, the colour of my skin becomes dark. And it becomes normal when I come back to Delhi. Please tell me the reasons behind this.

A:It is due to the high quantum of exposure to ultraviolet rays (in sunlight) in hills that gives rise to tanning. That is why, on expeditions to hills, it is advisable to use high SPF sunscreens like Sun ban, Shade lotion, etc. It should be used in the morning before going out in the sunlight, in the afternoon, and at 4PM in the evening.