Agree with Dr Varun Choose a sunscreen depending on skin type and level of sun exposure.  Skin lightening treatments and Lasers are available at Dermatologist clinic. However they can be done only after evaluating type and cause of pigmentation.

Pigmentation has many causes that can be ascertained only after examining the skin. However most important thing is avoidance of sun exposure and regular use of sunscreen. Rest of treatment can be done only after making proper diagnosis.

for pigmentation:- Increase intake of water & citrus fruits . Sun protection is important . Photostable Gel SPF40 / BIODERMA Photoderm AKN Mat SPF30 / La Roche Posay Anthelios XL SPF 50 Dry Touch as sunscreen to be applied half an hour before sun exposure. Apply Biluma Cream/ Melaglow Rich cream for application once at night for 2 months.