Civil Service Personnel Rules Rule 278

278. In making entry of the date of birth of the service personnel:
(a) the date of birth shall be recorded after scrutinizing any of the following documents:
(i) birth certificate;
(ii) school admission registration;
(iii) certificate of passing matriculation examination;
(b) in the case of service personnel who knows only the year and month of birth but does not know the date, the 16th day of the month of birth shall be deemed as his date of birth;
(c) in the case of service personnel who knows only the year of birth but do not know the month and the date, the first July of the year of birth shall be deemed as his date of birth;
(d) if no evidence can be submitted for the year, month and date of birth, the age mentioned in the medical certificate of fitness shall be deemed as the age of such service personnel. However, for the date attaining that age, the date on which the service personnel underwent medical examination shall be deemed as the date attaining the estimated age in that medical certificate. Therefore, the assumed date of birth of the service personnel is the result number by subtracting the estimated age in the manner mentioned aforesaid from the date of medical examination.