I am a fresh applicant and below 15 years of age. Can I include my step mother's name as my mother in Indian passport?

If it's asking about your birth mother - and I assume that it is - the answer is no.

My birth mother never had seen me, nor I am. She died after giving birth; cardiac arrest during caesarian operation. My step mother look after me since birth, later married to my father. I do not know anyone other than her as my mother. What is the procedure to use my step mothers name as my mother in Indian passport?