Why PPF scores high on safety
There are different aspects regarding the safety of PPF.
Any sovereign backed investment (which means it is issued by the national government of a country) stands for the highest safety.
Since the funds in PPF are backed by the central government, the investment does not get any safer than this because the government will not default in its payment.
The second aspect is that the return is not subject to market fluctuations. The return, though reset periodically, is assured.
Moreover, the amount in a PPF account cannot be attached under any court order with respect to any debt or liability of the account holder.
While it was given to understand that the Income Tax authorities can attach the account for recovering tax dues, the court has ruled otherwise.
PPF: Public Provident Fund
(Source: Taxguru.com, Tax blog, Taxvani.com)