Hi Vimal,
Good luck preparing for the RHCA exams. I am preparing for RHCSS myself and will attempt RHCA after that (if all goes well)
I hear it is on par with the CCIE exam in terms of difficulty. You'll have to take five endorcement exams spanning over 5 days on the following subjects.
Security: Network Services
Deployment and Systems Management
Directory Services and Authentication
Storage Management
System Monitoring and Performance Tuning
The RHCA exam is not offered in India yet so you may have to travel to Singapore or Australia.
By the way, have you taken the RHCSS exams or are you going directly for RHCA? If you have I'd really appreciate some pointers.
Best of luck!