To delete Gmail account permanently, first log in to Gmail account and visit Products tab from your account settings. Then click the Edit link from your product page. Then click the Remove Gmail Permanently link from next page. After clicking the link new window will open and it asks your Gmail password again. You have to give any email id this will become the email address with which you sign in to your Google account after you delete the Gmail account. Then click the Remove Gmail button, then Gmail team will send you mail link to confirm login to your email id, then click the link to delete your Gmail account permanently.