To protect the Library documents from the destructive agents, which are mainly of two kinds; (i) Elemental, namely heat, moisture, dust and dirt, which damage books in an indirect manner; and (ii) Physical, such as insects, pests and fungi which cause damage to books directly. Moulds, mildew, bacterial and certain vegetable growths such as lichens and fungi are the main destructive agents of the second kind.

As soon as mildew makes its appearance, the books are taken out, dusted properly, dried, aired and the book-shelves thoroughly cleaned. If any book has been attacked by a destructive agent or shows even the least sign of decay, such book is segregated from the rest for fumigation