Guess you are in a important event which is a few hours long and its hard to accept calls. Its not possible to switch off your mobile phone because there are chances that if you do this, you may not be able to accept the emergency calls, hence in any case its important to keep the cell phone ON, but sometimes Tele-marketers don’t understand the importance of others time and they keep redialing your number until you accept the call and speak to them. Hence its important to Block Unwanted Incoming Calls.
Android Phones have a nice feature of blocking or blacklisting some specific numbers which you don’t want to accept nor ever get disturbed with. The first step to get started with this is to store this specific number in your contacts list under some temporary name, say – Tele Markerer 1 and save the same under your contacts.
Under the contacts, you need to select this specific contact and then tap on the options menu which will display a option to set the Incoming Calls to be directly sent to your voice-mail. This will kind of block this specific number to be displayed on your phone while you are busy at work or some event.

good and informative