@user17591658047 agreeing with my colleague @Opus 17 , under article 19 para1, your govt. pension for services rendered to India, the pension distribution is only taxable by India
Your passive earnings ( interest / dividend etc. ) are however taxable in US. India may also tax these incomes.
If India taxes these incomes and you wish to avail of foreign tax credit, then you have to file a return. Additionally if the gross world income ( exclusive of Govt. pension) is above the deduction ( itemized ), you probably have to file a return.
My general sense is that ( especially given the current political environment) it is probably better for you to file a 1040 return showing your world income ( pension, passive income etc. ), excluding the pension income ( as negative "other" with notation " US-India Tax Treaty article 19 " and claiming Foreign Tax Credit ( if there is any passive/interest earning taxed by India ) --- note that because of US and India tax calendars being different , you may have allocate the incomes according to US tax Calendar. This should result in nil to very little US taxes.
Assuming that your GoI pension and interest earnings are deposited into an Indian bank account, as a US person ( citizen/GreenCard/Resident for Tax purposes ), you do come under FBAR ( ONLY on-line form 114 at FinCen.gov) and FATCA ( form8939 along with your form 1040 ) -- see requirements here -->
Comparison of Form 8938 and FBAR requirements | Internal Revenue Service
I am assuming from your post so far that you are living here with GreenCard with family and therefore may not be moving funds between India and US. However, note that any movement of US$10,000 or more ( domestic or international) always result in SAR ( Suspicious Activity Report ) being raised by US bank as a matter of course -- no impact on anything.
Is there more one of us can do for you ? You can post here or PM me ( just NO PII -- Personally Identifiable Information)
Namaste ji
