Hi Sunil,
Premature greying of hair can be mainly hereditary, but excessive tension, stress or anxiety can also be the cause.
* Deficiency of nutritients specially copper can reduce the production of melanin.
* Avoid lot of tea, coffee and alcohol.
* Eat foods rich in protein, iron, minerals and vitamin A and B.
* Apply amla mixed with coconut oil to you scalp regularly.
* Grate some fresh ginger. Mix with honey and place it in a jar. Eat 1 teaspoon everyday.