1. Was the said Development Agreement Registered?
2. Was there any clause in the Agreement specifying he period within which the Developer shall have t start and complete the development failing which he greement will automatically be treated as terminated?
3. If yes, then you can invoke the said clause and send him a letter informing him that the said agreement stands cancelled,
4. If no, then you can simply send him a letter stating that the development agreement will be treated as cancelled if he fails to start construction work with in one month from the date of receipt of the letter,
5. He can do nothing legally for your erminating the unregistered agreement after wo ears of its execution for not staring the construction work.