how to block those unwanted calls?

how to block those unwanted calls?You can do it so by registering in the national “do not call registry”.
First join the do not call registry.http://ndncregistry.gov.in/ndncregistry/index.jsp This will maintain all subscribers list who have opted for “do not disturb service”A telemarketer will lose his license or face a fine of 500 Rs per call or sms he sends you after you register to DND service.

Stop unwanted calls in Airtel:

Airtel postpaid and prepaid mobile users sms “START DND” to 121 and broadband and landline customers call 121.

Stop Unwanted Calls on Vodafone:

You need to send a SMS ACT DND to 111

Block calls from reliance:

http://www.reliancecommunications.co.in/Communications/Rm/rm_index.html and fill up a form to register to dnd.

Stop Calls on Idea Callular -

Call up 1909 to register to DND.
or SMS “START DND” to 1909 and for un-listing / de-activating DND send “STOP DND” to 1909.

Tata Indicom:

http://www.tatatele.in/dnd/DNDAction.do use this link to activate DND.

Tata Docomo:

If you want to register yourself on the NDNC registry, simply SMS START DND to 1909 (toll free) and in case you want to de-register yourself from the NDNC registry SMS STOP DND to 1909 (toll free).

BSNL:

http://pdnc.bsnl.co.in/
Interactive Voice Response System (IVRS) – Call Toll-free number 1909 and follow the IVRS instructions for registring/de-registering.
SMS – Send SMS to 1909 with keywords ‘START DND’. It will be registered. For de-registering SMS ‘STOP DND’ and it will be dergistered.