Purchase of flat

There is no problem in buying the said flat. Consult a good lawyer especially with conveyancing background to prepare the document of sale. And mention the descripttion of the property with caution and details.

Additionally I wish to add ---- In Specfic Relief Act 1963 there is provision of REctification of Instrument as per Sec. 26 . Affected person need to approach court. I feel you need to make all party and get it rectified. I think better you do it . Property people keep for decades and some time generation . You never know where problem arise , initial hard work give better result in future.

Anyhow if you are doing systematcially with the help of local experienced lawyer as mentioned above and my additional point , with also checking documents from good property advocate certainly your transcation can be safe. Try to get Titile certificate too from local advocate (Although due to discripttionary myself bit doubtful but still he can say he has checked remaining documents .like land record, building plan sanctioned etc.) 

sir first verify the permission plan issued by MCH if in the permission plan there is a fourth floor is permitted or not if not it mean builder is constructed the stilt floor as ground floor and marked as         G-101 like wise the flat numbers are marked and also obtained abstract of Tax from GHMC    

Thanks Ahmed

I feel you added some thing more to my knowledge.

This builder may have done some misinterpretation in building plan. Before purchsing flat in this building whole building Plan with Occupying certificate /Completion certificate is required to be examined by architect or person who is good in reading Plan (May be as you say there can be some serious discripttionary in Plan and reality) (Word Occupying certificate & Completion certificae i used because in Maharashtra it is called that under MRTP Act. So in your state you need to check what are terms for it)

Local municpal tax to required to be verified