Source: TRAI Research paper on DTH Interoperability in INDIA.
It seems GOI is planning on implemeting CI CAM modules in future which will just need us to insert DTH Smart Card in correct CAM to descramble the signal.
Airtel & TataSky using NDS ( Videogurad ) increases decryption complexity.
Best is DishTV/Sun/Videcon for the descrambling job in Windows/Linux with correct CAM available through ebay .
Check this "Strong Conax CAM CI CAS7 module for DVB-T, cable (DVB-C) and satellite (DVB-S and DVB-S2)"