Hello Deepak, As regards determining date of birth, the provision in the Standing Orders applicable to you offers the decisive test. Normally it is the school leaving certificate. But if he is illiterate, what was the date he declared at the time of joining.You had mentioned 1960 was in the ESI Card of previous employer, but did he mention so in his application for employment. Then it can be relied. Otherwise ESI Card, Adhar Card are not verified documents for age. The certificate of municipal/panchayat authorities can also be relied.