The certificate of registration issued to a “casual taxable person” or a “non-resident taxable person” shall be valid for a period specified in the application for registration or for a period of 90 days from the effective date of registration, whichever is earlier. However, the proper officer, at the request of the said taxable person, may extend the validity of the aforesaid period by a further period not exceeding ninety days.
(ICAI FAQ PUBLICATIONS 06-09-2017 REGISTRATION: FAQ NO. 21)