How difficult is it to get a PhD from IISc Bangalore?

Well, getting a Ph.D. from IISc is indeed difficult. In my opinion, the true meaning of a Ph.D. is investing your entire efforts, time, and knowledge in one specific region. In India though, Ph.D. is just considered a degree one can achieve by publishing some paper in some conference or journal. The quality of these papers is poor and substandard bringing down the sort of the degree. 

However, IISc being a prestigious institute has managed to maintain the dignity and credibility of the degree so far. You need to prepare yourself for committing to hard work and high-level dedication. Know that your next 5-6 years will be spent proving and disproving every hypothesis possible and conducting infinite experiments.

As a Ph.D. student, you will be publishing a few journals in top international forums and also writing your own thesis, which will culminate your entire work and present it before other researchers and professors of the institute. You will then be assessed thoroughly. Only after proving your point strongly and convincing them will you be able to get the degree. 

During this whole time, you will face many struggles dealing with your PI and securing funds for your research work. But trust me the result will be worth the effort!