A free service is offered by the website.
This service will check for National Do not call registry status.
This link will navigate you to check the service status.
Click here
Just open the webpage and enter your mobile no and you will see the results
If your details comes in output then your mobile no is registered for DND service.
If you get this message
"This Number is not an Active DND Number."
then you need to register your mobile for DND service by opening individual operators websites.
If you want to know how can you subscribe for DND service Contact me. I will provide you lnks for registration of the service.