Aircel — discontinuing of sim card due to closure of company

I owned a mobile number which was provided by aircel. I still have the sim card. However, since aircel shut its business that number is not operational anymore. I have also tried to reach out to the number, it has not been provided to any other customer also which means it is still available.
This number is linked to my aadhar but i cannot use it, and hence i cannot link my aadhar as well to my accounts which causes a lot of trouble.
Please let me know how this number can be retained again on a different mobile operator.