It is Hardest mostly because it is designed in such a way to eliminate majority of students, this doesn't make it good. Most of the top universities in the world are in US. Most of the IIT passouts want to pursue their masters from those universities if possible. So your argument that it is 2nd Most Hardest doesn't mean anything. Most of the tech innovation which we have seen in the previous century as well as this century was mostly because of those institutions which were designed for the benefit of students rather than fake certificate of being hardest. As for ICSI it is considered hard mostly because of its literature, which is again latin/old English making it hard for us as Indians. Aside from literature Most of the maths and science is equivalent to cbse(somewhat harder than cbse) but doable. This doesn't make it harder than every other board across country. Hardest boards in India are UP board and Bihar board(If you will see their avg % you will realize). I didn't framed my previous paragraph well, that's why many are misunderstanding that I'm trying to say that JEE/NEET exams are not hard, but I'm saying that this obsession of Indians with "Hardest" is nothing but a coping mechanism for their shitty education system. The early we realize that if something is abnormally hard doesn't mean it is better, would save a lot of students lives(not possible).