Hi Mani,
If you ask best institutes, it always differs from different person on different experiences. The best suggestion, you can call SAP Certification India and check with them, when the SAP Mobile certification batch is starting and which institute offer this course.
You may get the dates two or three months in some institutes, because they need to get at least 5 students to train in SAP Mobile certification. Sometimes, SAP itself taking classes for some niche skills and rare SAP technologies.
So, you can get an idea if you contact SAP India on above link.
Best of luck.
Regards
GGOPII