There is no medical treatment available or till now invented by science which can make you fair. What you should aim for is healthy and glowing skin.
Skin colour is determined by your genes which cannot be altered with any treatment.
That being said, tanning often contributes to additional darkening of skin, and regular and correct usage of sunscreen can help prevent further tanning.
Detanning creams and skin whitening treatments are available which can help you to a limited extent, kindly visit a qualified dermatologist for further treatment.
Next Steps
Regular usage of medicated sunscreen, consult dermatologist
Health Tips
Avoid excessive sun exposure