Lemon is a natural antioxidants and is rich in Vitamin C, and both are good for our skin. So if you want to lighten your skin colour then lemon is also a good option.
Simply take the juice of lemon and add similar quantity of water in it, use it on alternate days by apply the lemon water on your face and rubbing it.
Another method is making a face mask for which you have to add two tablespoon honey with lemon juice and powdered milk. Mix it well and apply on your skin, leave it for 30 minutes and then wash your face with warm water.