​As a general rule, India has same copyright rules as the rest of the world, since India has signed the same international conventions as other countries. 

Again, in general, nothing can be copied without permission until 60 or 70 years after the death of the copyright holder.  Critical editions can be copied 25 years after publication.

If you are a copyright-holder and you want to let others copy your work but not to take undue advantage of your generosity, then you should consider placing a Creative Commons license on your work.  This way, you keep the copyright, but you give permission to others to reproduce your work under certain terms that prevent abuse.  This would be good, for example, for an article that you would like your students to be able to copy, or if you want to put a PDF of your work on your website or on a service like Academia.edu.

Best,
Dominik