Which chemical peal should i use to lighten skin tone please? (for normal brown indian combination skin).

None: Peals are likely to damage your skin and make it darker. You may use sun screen to prevent tanning. As you say, normal brown complexion of an Indian, is normal, leave it alone. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.