guideline from Ministry of Home Affairs, India regarding issue of VISA is
available here.

embassy might require the letter from the Indian Government approving the
Conference. Please click below links to download approval letters from Ministry
of Home Affairs, Ministry of External Affairs and Ministry of Human Resource
Development (MHRD):

Security Clearance:  to be updated soon
Political Clearance: to be updated soon.
Clearance from MHRD: to be updated soon.