23 December 2014
From my understanding of your question, if the provisions of DTAA between country where the given person resides and India are more favourable than the provisions of the Indian law, then such person can take benefit of the relevant DTAA. If a particular DTAA article suggests non deduction of tax on a particular transaction, then the same can be used by such person to avail non deduction of tax without violating any Indian law.
23 December 2014
Section 90(2) suggests that the provisions of the IT Act, 1961 shall apply to the assessee to whom such agreement applies, to the extent such provisions are more benficial (Than the DTAA) to that assessee.