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SMS messaging regulations and restrictions

Several restrictions are in place regarding SMS messaging in India, particularly when it comes to the country’s National Do Not Call (NDNC) list (see more in the table below). There are other restrictions in place regarding sending times and volumes, which you can also see below.

Restriction Description
Sender ID
  • Sender IDs (the from address displayed on recipients’ phones) to be used must be pre-registered beforehand, along with the template of the message to be sent to India. Any message sent outside of these Sender IDs and message templates may be dropped before delivery and may still be charged to the sender.
  • To manage Sender ID in India, Clickatell sends all messages with a pre-approved six-digit alphanumeric sender. Numeric senders are not allowed.
National Do Not Call list (NDNC) A substantial portion of mobile numbers are registered on the NDNC, and if you send marketing or promotional messages to these numbers, your message will be blocked (you can still send transactional and manually approved messages to these numbers).


It’s a good idea to check the NDNC to see if the number you want to send to is registered (omit the international dialing prefix of 91 before searching).

Promotional and transactional SMS
  • Sender ID for transactional SMS messages must contain six alphanumeric characters and must be pre-registered.
  • Sender ID for promotional SMS messages will be replaced with an assigned short code from the operator.

Note: No promotional content should be routed through the transactional route.

Time restriction Promotional SMS messages may only be sent between 9 am and 9 pm standard India time. This means your messages could be blocked or delayed if you send outside of these times, depending on the operator.
Volume restriction You may not send more than six messages per hour with the same content, from the same sender to the same number.
Restrictions on messages with stock-related information Transactional routes cannot be used for sending any messages relating to stocks and/or shares. To use transactional routes for stock market activities, you’ll need to get certification from stockbrokers and/or entities registered with the Securities and Exchange Board of India (SEBI).


The certification must follow the guidelines below:

  • Certification must be written on the entity’s company letterhead.
  • The entity should be registered with SEBI.
  • An entity should mention the command line interfaces (CLIs) to be used by them and the nature of the messages/content to be used.
  • Purchase order validity.
Restrictions on opt-in messages
  • No opt-in messages should be sent via transactional routes.
  • An opt-in message can be sent to the end-user only if they have submitted a documented approval.
  • Web opt-ins are not accepted as approved opt-ins.
Restriction on social invites Any invitations related to social media/websites/OTTs need to have their content confirmed and whitelisted before being sent via transactional accounts, and violating this can result in heavy fines.