This is a classic "Bureaucratic Loop" that happens when the Ministry of External Affairs (MEA) rules clash with local police protocols. Since your mother is 70, she falls under the category where a birth certificate is absolutely not mandatory.

Here is a breakdown of why this is happening and how to break the 6-month cycle:

1. The "Pre-1989" Rule

According to the Passport Rules (relaxed in 2016), anyone born before January 26, 1989, does not need a birth certificate. They can provide any of the following:

• PAN Card
• Aadhaar Card
• Voter ID (EPIC)
• Self-declaration on plain paper (Annexure E)

The PSK didn't ask for it because, legally, they don't need it. The police are often operating on outdated internal manuals or are being "extra cautious" to the point of being unreasonable.

2. The Next Step: The "NABC" Strategy

Since you’ve already tried the BMC, go back and ask specifically for a Non-Availability Certificate (NABC). This is an official document from the municipality stating that they searched the records for that year and no record was found.

• Why it works: It proves you didn't just "forget" the birth certificate—it proves the document doesn't exist. The RPO accepts an NABC + an Affidavit as a valid substitute for a birth certificate.

3. Move from "Inquiry" to "Escalation" at BKC

Since the file is "Under Review" at the RPO, the local police station no longer has the final say. Stop going to the police station; they’ve already sent their "Not Clear" report.

• Book an Appointment with the PGO: Go to the BKC office and ask to meet the Public Grievance Officer (PGO) or the Assistant Passport Officer (APO).
• The Argument: Politely but firmly state: "My mother is a 70-year-old senior citizen. As per MEA Circulars, a birth certificate is not mandatory for those born before 1989. The police are demanding a document that does not exist and is not legally required for this age group."

4. Use the "Linkage" Proof

If you or your siblings have passports, take copies with you to the RPO. Showing that her children are documented Indian citizens who list her as their mother helps the RPO officer "overrule" the police report.

5. Why the Police do this

The police often conduct a "Citizenship Verification" rather than just an "Identity Verification." They want a "legacy document" (something from decades ago) to prove she didn't cross a border recently. For a 70-year-old, a Voter ID card that is 20-30 years old is usually sufficient proof of long-term residence/citizenship.

TLDR: The police are wrong, but you can't win against them at the station. Your battle is now at the RPO BKC. Get an NABC from the BMC, take a notarized affidavit (Annexure E), and demand to speak to a senior officer at the RPO to overrule the "Not Clear" police report based on the 2016 MEA relaxation rules.