Any unauthorised alterations made in flat can be demolished by bmc after issue of notice 

You are entering into illegal contract. If later builder refused as promised, you cannot do anything.

And if anyone complained of this variation, you may face demolition.

1. Irrespective of the any sanctioned Plans, no changes are permitted after buildings are granted OC by BMC.  Any changes (after OC is granted) shall be illegal & unauthorized and the occupant (present owner) shall be responsible for the changes and shall be liable for prosecution.

Dear Client,

If there is a minor Change in the structure of the building, it does not matter. And if the change is costing more and seems improper then you may file a in the RERA agaist the builder.

Yes, your apprehensions are correct. 

You can't change in the structure of building  after OC which is approved by the competent authorities under the law. 

If changed then MMC would issue you demolition notice under section 351 and 354 - A of MMC Act 1888.

You may be charged with criminal actions under MRTP Act if the changes brought to the notice of MMC and Police.

Better not to change the structure after grant of OC.

Rera first of all does not issue any OC

The sanctioned plans are just required to be uploaded on the Rera website by the builder

Once OC is received there can be no structural changes in the flat which tend to increase its total carpet area except minor cosmetic repairs 

Builder will be bound by the plans which are approved by the Municipal Corporation 

Any other plan is simply illegal and cannot be relied on nor can any changes be made as per that plan

Once OC is issued the builder has to immediately give possession of the flat to the buyer. He is not permitted to make any changes to the flat which will invalidate the OC. 

When you take possession of the flat you will have to ensure that the flat is constructed as per the sanctioned plans and not any other plan. If there is any deviation you can either refuse to take possession or take possession under protest and notify about the unauthorized changes made by the builder to the Municipal Corporation and further you can also approach Rera to compensate you in case the Corporation takes any steps to demolish the flat which is not as per the plans 

This is nothing but a deviation in the approved plan.

This deviation which has not been approved by the competent authority will always be a thorn in the throne.

This may attract  either penal provisions or even demolition action by the competent authority at a later stage especially when the builder departs from the scene post sales of this property.

You may better obtain a proper legal opinion from an experience lawyer and proceed only  if recommended.

Yes it will definitely be an unauthorised structure if not as per OC

- If OC already issued to the said building , then no alteration i.e. the builder cannot change the structure legally. 

- Further , the flat owner can face trouble in future due to the said changing in the plan. 

The flat which is aligned to you kint check that building comes under RERA and layout plan as per OC. If it's on not matching than do not purchase.

Yes if the builder has built an unauthorized structure then it will create problems in the future. He cannot be given a CC in this case.

The building constructed without sanctions or deviated more than 5 per cent from approved plan levies penalty and authorities has right to demolish the building without any prior notice.

Yes it will create problems in future for reselling or loan

No, you can change internal structure of flat after recieving possession of flat if that change doesn't affect safety of building. 

Dear Sir/Madam,

You are suggested that you are right in your perception and there may future issues in that.