According to WHO, exclusive breast milk is given upto –

Exclusive breast feeding : The baby should be given only breast milk and nothing else (not even water) for first 6 months of life. Weaning should be started by 6 months of age with semisolid food, in addition to continuing breast feeding. The WHO recommends exclusive breast feeding for the first six months of life and then breast feeding up to two years or more.___ Internet Complementary feeding means giving the child other nutritious foods in addition to breast milk. Breast feeding is sufficient food for first 6 months. Thereafter, concentrated energy dense complementary foods are essential in order to maintain an adequate velocity of growth for the infant.