I agree with my lrd friends and further add ;-
In Every Develoment agreement the terms will be fixed and the Scheme of the Development will be according to the Terms . The Demand of the Land owners is out of the Terms of the Agreement the same is to be specified in the Reply Notice
It is General Clause in all the Development Agreements that the Land owners shold not interfere or try to stop the Construction , for the delay / damages /loss caused by the Land owners to the Builder shall be reimbursed by the Land Owenrs .
Verify the Terms of the Development Agreement and reply the Notice stating that their claim is illegla and with out any basis under the Development Agreement . The Agreement Temrs will be the reply to the Land Owners . They have no right to claim more amount as and when the project locality petentaility is increased , the claim would be against the Agreed Terms .