How Police Trace Mobile Number in India with exact name & location

1. When your phone is off, police contacts your service provider to give the details of calls made in a specific duration of time. So they can get the last location of yours from there. This is basically because you connect to a tower of the service provider to make calls/SMS/etc and the provider records the same. Therefore, some details regarding the call, your phone, and the tower are stored with the company.
2. When your phone is on, police can track you through triangulation, as mentioned in one of the other answers. Again, you're connected to a tower and can be detected easily.
3. Apart from this, police can get the documents you submitted while buying the SIM card and get your details from there.
4. Also, android keeps a track of location history by default. That too can be used if the police are able to get access to it through Google etc.
5. IMEI is a phone (and a dual-sim phone has 2 IMEI). Every time you make a call, your IMEI is taken note of by the service provider, which is reflected in the details of calls as mentioned in Point 1.
6. You can be tracked by IMEI or Phone number as both are recorded in call details.