Not long ago, the inclusion of a bio data section that contains information such as Date of birth, City/town of birth in CVs was an unwritten rule. But lately as a result of legislation in some developed countries of the world, you are no longer required to include your age in your CV or resume, now my question is this, what is obtainable here in Nigeria?. Is the inclusion of one's date of birth still sacrosanct while writing CVs in Nigeria or its Optional

It is not necessary at all. Unless the company you're applying for needs it. Generally, you don't have to put it