N.B: It is to be mentioned that the functions of world bank is not like other conventional banking system. It’s income source is not only interest but also donation from many countries.
Ref. No. 41/1059
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
It is permissible, for this job does not involve consuming interest, or writing it down, or witnessing it, or helping those who do that. Moreover the wage he is receiving from bank is not from interest only. (Fatawa Usmani)
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband