Ppf

Sec. 80C(2)(v): “as a contribution to any provident fund set up by the Central Government and notified by it in this behalf in the Official Gazette, where such contribution is to an account standing in the name of any person specified in sub-section (4).”
.
Sec.80C(4): “The persons referred to in sub-section (2) shall be the following, namely:-
.
(a) for the purposes of clauses (i), (v), (x) and (xi) of that sub-section,—
.
 (i) in the case of an individual, the individual, the wife or husband and any child of such individual, and
.
……..”
.
It doesn’t matter whether he/she is major/minor, dependent or not, married or not etc.
.
Hence, contribution paid by the assessee into the PPF account of his major son will qualify for deduction u/s 80C, since the section refers to account in the name of any specified person and any child.