Can I study textbooks with exclusive rights and teach in India? Assume a textbook T having a high cost. And T is not available anywhere for free.

Suppose I personally brought T and read and understood completely. 

Am I allowed to teach using it in India? Teaching here refers to either classroom teaching, being a faculty or commercial teaching, acknowledging source.
I can't speak to what would be allowed or not in India, but consider this: is it good for the students if the textbook is really expensive?

Are the students supposed to read the textbook themselves? If it's really expensive then you can get the following problems:


They don't use the book because they can't afford it.
They use a pirated version of the book.
They spend a lot of money on a book and get into financial difficulty.
Only rich students can take your class.
They complain about the lecturer who insists on using an expensive textbook.
They use a different textbook that they can afford, and you have to deal with the differences that will surely arise.