Mobile/Telephone(Landline) users who do not want to receive commercial communications, then they can dial or SMS to 1909 (toll free number) and register in either of the two categories:
Fully Blocked Category- stop all commercial Calls/SMS
Partially Blocked Category- stop 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. For 'partially blocked category', send SMS 'START' with one or multiple options from the list of seven categories.
Total of 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.
Eg: To receive messages relating to only Consumer goods and automobiles, then send SMS "START 5" to 1909. Similarly, for receiving messages relating to Real Estate and Banking/Insurance/Financial Products/Credit Cards, send SMS "START 2,1" to 1909.

Do not disturb (DND) online services are provided by Government of India's Telecom Regulatory Authority (TRAI). DND Call/SMS applicable to all the telecom companies(Public sector/Private sector) in India. Major private sector companies are Airtel, Vodafone,Aircel,Idea,Spice,MTS,Reliance,Tata Docomo etc and Public sector company is Bharat Sanchar Nigam Limited (BSNL)