I have found out from google search that the same position I have applied had been published three times in the last three months discreetly. At different sites I found the following info about the same position from the same company:
It was published between 02 March upto deadline 30 March.
It was published between 03 April upto deadline 29 April.
And the latest published between 05 May upto deadline 25 May.
What could be the reason they have done this way instead of keeping it open until they find the right candidate?