Police Verification insisted on birth certificate (I am 1980 born)

I applied for fresh passport (Herald House ITO) and my file was granted and sent for police verification. My date of birth is 20.04.1980, which is there in my 1. Class 10 certificate 2. PAN 3. Aadhar 4. Voter id And last two documents carry my current address which is where I am staying for last five years. I own a 3bhk property in Malviya Nagar, South Delhi. However, when today the police officer visited my premises, as my wife opened the door the first thing he asked my wife if we are Bangladeshi. I didn't know that, it was only after the officer left, my wife told me this. The thing is, the officer kept on insisting on my birth certificate, and when I said that I don't have that. Because I was born in Kolkata, and I am a Bengali, he kept on insisting. Any property documents at the time of my birth etc. How on earth I am to get them, my father and my grandfather are both dead. I am an Indian taxpayer for last 15 years, I work in a Delhi University college as Assistant Professor (but technically that's not Govt service as we are autonomous) but he kind of made me feel like a Jew being doubted and interrogated by a Gestapo. To the best of my understanding birth certificate is not required if one is born before 1989 to get a passport. The police verification report has not come yet but I am planning to fight a legal battle. I don't have any high connection, I am a private citizen of this country but I have a right to get my passport without being unnecessarily humiliated, I believe. What should be my course of action assuming that this verification report might be hostile to me? Please help.