Please note, this May be in the trial stage in some states and areas
Details of all SIM cards purchased with your Aadhaar number in your name can be found at the site below. Among them you can block SIM cards that stealthily use your Aadhaar number without your knowledge. This is a good service from Department of Telecommunications.
1) Open the above site on your mobile and type in your mobile number which is tagged to your Aadhaar Card.
2) It will send an OTP to your mobile number and after you have entered the OTP on the webpage, it will show all the mobile numbers tagged under your Aadhar card.
3) You can select and take necessary action as required.
Thought very useful for almost all mobile users : warriers.org
It is not yet working in Kerala also, I think.
The site has some limited location access. Hope they will update soon...