I want to know that I have been seen that on PVC cable it is for 70'c & on RUBBER cable it is for 90'c. I don't know why it has been written on the cable if the current carrying capacity of PVC is more... And Please tell me that What is the advantage of RUBBER insulated cable over PVC insulated cable?

The cable "Type" dictates its use.

For example, rubberized cable may be suitable for a chemical environment while the PCV would not be because it would dissolve.