S. 90 (4) of the Act, as inserted by the Finance Act 2013 w.e.f 1.4.2012 provides that an assessee, not being a resident, to whom an agreement referred to in sub-section (1) of s. 90 applies, shall not be entitled to claim any relief under a Double Taxation Avoidance Agreement unless a certificate, containing such particulars as may be prescribed, of his being a resident in any country outside India or specified territory outside India, as the case may be, is obtained by him from the Government of that country or specified territory. A similar provision has been inserted in sub-section (4) of s. 90A of the Act. Pursuant therto, the CBDT has issued Notification dated 17.09.2012 to insert Rule 21BA and Forms 10FA and 10FB specifying the manner in which the aforesaid Certificate of Tax Residency should be obtained.