Go to your Gmail account and log in with your email and password if asked to.
Click on the cogwheel icon at the top-right corner of the page, and select "Settings" in the menu that opens.
Click on the "Accounts" tab, and then on the "Add a mail account" link as shown below:
Enter your full rediffmail.com email address in the window that opens, and click on the "Next" button.
In the next step, select the "Import emails from my other account (POP3)" option and click "Next".
Enter your full email address again in the "Username" field.Enter the password to your rediffmail.com email account in the "Password" field.Important:Important: select the option to "Leave a copy of retrieved message on the server".
Enter pop.rediffmail.com in the "POP Server" field.