No idea about this, maybe some issue with NSE website. Also, Bank Nifty was around 24k - 25k in October and 29000 was 5k - 4k points or 50 - 40 strikes away, so chances are it might not have been traded at all, that is why it might not be available, not sure though.
Any rule is followed while listing the options?
Example, 5500ce is not listed but 12500ce is. How is it decided? @ShubhS9
This is strike price scheme for Nifty Options, at a time there can be 30 ITM, 1 ATM and 30 OTM Option strikes. You can get detailed information on this here.