In India Bulk SMS is categorized in two types, Promotional (will not deliver on DND numbers) and Transactional (Delivered on DND numbers) For each kind, you need to have SMS aggregator which acts as an intermediate between you and the operators and provides the platform for submitting SMS and Data on which you need to send the SMS.
There are lot of aggregators who make reseller so it may be possible if you are looking for the service provider you'll encounter them and thus your process will have one more step.
This is the basic flow of the SMS and for setting up the SMS gateway you need to talk to operators asking for the services which in itself is a whole lengthy process and for that make RFP to operators. for more Detail Visit https://www.smsgatewayhub.com