How to Block unwanted Calls and SMS in India

Don't want to read the whole post?
just do this: on your device type "START 0" and sms it to 1909. Then follow the sms instructions.
for further details read below.

People are generally confused.. or just have been ill informed about how to do this, so i decided to post a definitive guide on the subject.

To start with there are 2 things you can do. both seem to have had some effect on reducing the number of calls/sms i get from that scum of the earth that is the telemarketer.

Step 1
Register on the DND(Do Not Disturb)List
This is a service that your service provider will provide, you just have to look for it on their website. Since these website's keep changing, theres no point me posting links to them. But trust me theyre there. You should be able to find it fairly easily especially if you're already registered on their site(for paying bills, etc.)Just google "DND (add the name of your service prvider"eg: "DND Airtel" and you'l find it faster.

Pros: actually blocks a fair amount of unwanted calls
Cons: 1) still allows authorized telemarketers(guys who have arrangements with your service provider) 2) Somewhat difficult to find the web pages, numbers etc needed to register with.

Step 2
Register on NCPR (National Customer Preference Register)(heres the website)
This is the service started by TRAI, and is difficult to circumvent by your evil service provider and their telemarketer buddies.

the procedure for this is quite simple:
Customers (landline and mobile) who do not want to receive commercial communications can dial or SMS to 1909 (toll free) and register in either of the two categories:

Fully Blocked Category- stoppage of all commercial Calls/SMS
Partially Blocked Category- stoppage of all commercial Calls/SMS except SMS from one of the opted preferences

For registering option using SMS, for 'fully blocked category',
write "START 0" and send it to 1909.
Then follow the sms instructions.

For 'partially blocked category', send SMS 'START' with one or multiple options from the list of seven categories.

There are at present 7 preferences to choose from- Banking/Insurance/Financial Products/Credit Cards-1, Real Estate-2, Education-3, Health-4, Consumer goods and automobiles-5, Communication/Broadcasting/Entertainment/IT-6, Tourism-7.

For example: To receive messages relating to only Health products, then send SMS "START 4" to 1909. Similarly, for receiving messages relating to Real Estate and Education, send SMS "START 2,3" to 1909.

On successful registration, customer will receive an SMS confirming exercised options and a Unique Registration Number within 24 hrs. The registration will be effective within 7 days of placing the request with the service provider. The customers can check the status of their registration by clicking on "Customer Registration Status".

Customer can also change the preferences after 7 days of registration or the last change of preference.

Pros: 1) easy to set up. 2)Supposed to, and infact does block the rest of the unwanted calls
Cons:if you do get a call/sms, you need to manually report it by lodgeing a complaint (by dialing or sending an SMS to 1909)

Note: both DND and NCPR registeration will happen with expicit knowledge/cooperation/whatever of your service provider.. so ya.. its probably not going to block 100% of those stupid calls.