Tarun: If the project is already listed in the database, you will need a good reason to have it deleted, which would usually be that the project has been cancelled and is not going to be made, or that it was an error and never should have been submitted in the first place.
To submit a request for deletion, go to https://help.imdb.com/contact. Click "IMDB Fan/Contributor questions", then select "Titles", then select "Delete a title", then click "E-mail". On the next screen, there will be a form for you to send an e-mail to the staff requesting deletion of the title. Please make sure to provide a full explanation in the "Reason for deletion" section.