Since last 2-3 months manier times i've listened that CA degree is tuffest among GPSC, UPSC & other exams.
And Guiness book has choosen CA is tuffest. But actually position is something different because CA Inter is nothing against B.Com from Mumbai & Pune University or CA Final is nothing against M.Com from the same universities. See the result of CA in those places it's quite higher than other places because they used to play with therir mind. and many students not. So in their mind CA is such an Everest. But if u can apply your mind in correct way and present your self properly in the exam, CA is nothing.
So the entry in Guiness book is only a rumour, nothing else. Their is no confirmation on their official website. So keep thinking and get the things easy