1) you can object to carrying on construction of third floor 

2) request muncipal corporation not to grant consent for carrying on any construction without consent of other flat owners 

Even 3rd floor is illegal. On such small area of land, only g +1 is permitted, Highest +2. 3rd not in any case. It was your fault, why didn't you resisted construction of 3rd floor. Complain to municipality office.

1. If the second floor owner had purchased the property with roof rights, then he can legally construct the 3rd floor. If not, it will be deemed as an illegal construction and complaint against same can be given to the Municipal Corporation of Delhi.

2. Your entire query hinges on the fact whether the second floor owner had purchased roof rights or not.

Also enquire whether the 2nd floor owner has procured sanction of site plan of the proposed third floor to the municipal corporation of your area. If not, the construction work can be stopped.

A building can have as many owners as one likes there is no bar to that but constructing additional floors fully is an issue that can be resolved by looking at the rules governing the building and construction of houses in residential areas that prevails in Delhi. Municipal corporations generally set a bar to the no. Of floors ine can construct or percentage of construction.

Regards 

You still have all the rights you previously had. Only the no of owners have increased.

This whole unauthorised construction is illegal and it cannot be done the Transfer of Property in this case only affected for the Builder floor as per the previous sale deed in case there is any objection from your side you have to file injunction suit in the Civil Court in this regard

1.  If the third floor owner had been sold with the terrace rights, then he may also proceed with his plan to construct the balance 25% of the vacant space, you people did not check it when the first owner built the additional floor then, hence your objection at this stage may not be maintainable.

2.  This thought should have come to you when the third owner had built an additional floor at that time and could have brought it to a halt whereas you allowed tht to be built and subsequently that was sold to different sets of people.

Your objection to this at this stage may not be maintainable, you may also ascertain that that if the original purchaser of the second floor was having terrace rights.

1. Was the original 2nd floor owner authorised to construct additional floors as per the sale deed registered in his favour by the developer? Had he taken sanction for the said construction from the local Municipal Corporation? If not then the entire construction of the additional floors and their subsequent sales are illegal and void at law. So, no further construction thereupon can be made by the presenbt owner of the additional floor.

2. You should have objected to the intial construction of the additional floors by the original 2nd floor owner if he had no authority to make the said construction. If he was given the authority for the said construction by the developer, and has obtained sanction for the said construction from the Municipal Corporation, then it can not be objected now.

3. If not, then file a suit against the present owners of the 2nd and the additional floors challenging their sale deeds.

He can only construct if the same is his area. Otherwise no. He cannot construct in common areas. 

Yes it will definitely cut your building rights as the no of owners have increased

without permission of concern department third floor owner cannot construct. 

third floor owner need NOC from second and first floor owner. 

if he continue construction work you can complaint before muncipal corporation. 

Dear client 

You should have opposed the transaction when it was happened for the first time. 

Now your chances of getting the relief are low but you can try this to avoid your loss.

First of all find out about the permission of construction of floor from MCD.  If the floor is build without permission then file complaint regarding illegal construction of third floor. 

And find out that what is written on the sales deed of second and third floor owner as further sale cannot effect your share in the property if second floor owner has sold his 33% share then this will be divided among second and third floor owner.  As 16.5% each

1. As per the information mentioned in the present query, makes it clear that Rest 25 percent portion on the third floor is lying vacant or may be in use but not constructed yet, and now the new owner wants to contract the same left petition.
2. As per law, you may not be able to stop him as he would be constructing on remaining 25 percent out of the 100 yards.
3. But, yes it don’t mean that he won’t be needing your NOC, he would have to make sure that no nuisance gets created for you.
4. And also, he will have to seek permission from the MCD for further construction otherwise there are cases wherein whole building gets booked because of mistake to not to take permission by one person.
5. You can also ask for the permission from him, if he doesn’t show then please complain on police as well as in MCD.
6. Rest, you are free to call me at any time for further detail discussion on this issue.