How to deactivate SBI SMS alerts?

I could not find any way to deactivate the SMS alerts exactly as it means. But, if you are registered for netbanking, there is a way to disable the SMS alerts. I do not know whether it will deregister your mobile number and relieve you of making payment of charges.
Here is how you can disable the SMS alerts -

1. Login to your netbanking account.

2. Click on e-services tab.

3. Select SMS alerts on the left pane.

4. You will be given the list of your accounts associated with your login ID. Select the account you want to deactivate the SMS alerts from and click on Proceed.

5. On the ensuing page, you will find the SMS alert settings you can configure. At the bottom, you can see To disable SMS alerts, click here.

6. Clicking on the link will bring a confirmation pop up, click OK.

Your SMS alerts for the account you have selected will be disabled.

You have two options. One is from the netbanking account itself. Another is filling the form at SBI branch and submitting it to the account manager. That way you can disable your notifications on your mobile. Do note that the notifications on your netbanking takes 48 hours. And if you use the form in branch then it could take around few hours to as long as 72 hours depending on the account managers queue.

To get SMS alert deactivated, just visit the local SBI branch and submit an application for same. The service will be deactivated the same day.

However, in my opinion , you should continue with the service. It is very useful as in case you lose ATM or the account gets hacked online, you will get SMS for those transactions as well. This will help you take immediate action. Otherwise, it might be late to report it if you know about fraud transactions later.

I agree to what Timmappa has said and am not repeating the same steps.
Just to ensure you that it is the correct process, I can say, Log In to your online SB account, from the same e-services and SMS alerts you will get a small list of notification tips appearing at the middle bottom of the page saying, know More about SMS alerts. There you get this set of Question and Answer displayed:

"Can I disable all alerts for an account?
Yes. In the SMS Alerts Registration/Updation page, select an account and click the disable hyperlink. SMS alerts will be disabled after getting your confirmation in a subsequent page."

So you can go ahead with disabling the alerts, but even I suggest you to continue with the service as it will give you an extra level of security. Moreover, for OTP transaction too you will need the service as online Payment has become a part and parcel of our life.