I have searched PF code meaning for Pune - Maharashtra. It is showing PU/PUN. Generally my understanding is say for Karnataka First two alphabet is KN which means Karnataka state. So Maharastra it should be showing as MHPUN, but not sure why it is showing PUPUN instead of MHPUN.
But its showing PU/PUN. For Karnataka First two alphabet is KN which means Karnataka state so for Maharashtra why PU instead of MH.
EPO office are given a 2 Char Region Code and a 3 Char sub-Region Code. Initially it was based on States. However as the load increased, more region codes were added. Note not all states have Regions, these are members of other Region. This is done to load balance a region. If the region becomes large, it is broken into multiple regions.
So you can see MH continue for Maharastra with Bandra as the sub-Region. A new Region PU for Pune and PUN for Pune, SLP for Solapur, KOL for Kolhapur.
Similarly Karnataka has Multiple regions KA for wider Karnataka, BG and PY for Bangalore area; GB for Gulbarga area etc.