Indian Railways sister website, irctc.co.in not only allows online reservation but also provides easy interface to cancel the booked e-tickets.
Here are the steps for cancelling a booked e-ticket,
1. First login to irctc and go to My Transactions > Cancel e-ticket/refund.
2. Enter the password when asked and click ‘Go’.
3. You’ll see list of all booked e-tickets. Select the one you want to cancel. Next, click ‘Cancel E-ticket’.
4. Next you’ll be shown full ticket to verify if this is the ticket you want to cancel.
Click ‘Cancel e-ticket’ to proceed. [Click ‘Yes’ when prompted]
5. On successful cancellation of an e-ticket, you’ll be shown the cancellation status. That’s all!