Will Data privacy law end irritating sales SMSes?

When we shop at a stores like Big Bazar, we are asked for our phone numbers. After we do the payment, we receive an almost instant 'thank you' message. In the coming days this turns into a menace of unsolicited promotion message "30% off only for today", "tomato sauce only for Rs 19". All of this without an unsubscribe button. The only option here is to block these retailers. So, the next time you have to access your royalty scores at the store for some discount, you takeout your phone, unblock their number and then tell the OTP to the person at the billing counter. All this will change once we have a data privacy law.

How will data privacy law change things?
Once the law kicks in:

1. The stores will need to ask for your consent before taking your number. They will also need to inform you the 'purpose' for collecting data in an easy to understand language.
2. The purposes that they can collect data for will have to be limited by the 'data minimization' principle, which requires a data processor to collect data only when it is necessary to fulfil a purpose. So if data is being collected for accounting purposes, it cannot be used for sending promotional messages.
3. The data subject will have the right to withdraw their consent and right to erasure which can be exercised to make sure that the stores do not store your number or use them for advertising purpose.

So in a utopian future when India finally has a data privacy law- imagine going to a store, being handed a privacy policy at the door, being asked for your consent at the billing counter and saying no, I do not consent.