CDA Restrictions on building a house in Phulgran, Bhara Kahu

I am planning to buy a land in phulgran, bhara kahu, islamabad. Someone told me that cda has added a provision on those land that says that the buyer of the land will not build a house on the land, and will not resist cda access to that land. The plot is located near to korang river/stream, where there are some great beautiful houses with wide streets. Is that provision a part of cda seeking land for its new housing scheme? How such provision is justifiable if the land is a private property? What would be the future of these houses?