It's easy when you filter it through Indian culture. A combination of izzat, chaalaki, and jugaad. Izzat means you had better not fail or punish clan A's retarded kid for any reason or they'll kill you and your family for it. Chaalaki means they can sit there pretending to do schoolwork and that's more important than actually doing work. Jugaad means if they cheat on the test and win, it's a moral good. Then add their caste system and you'd have brahmin kids running around thinking they can order around the teachers and school staff (and thanks to izzat, they can).
Combine all that and you get a constant pressure to let people cheat and reward them if they do, to give people pretend awards and accolades and bend the bar ever lower so more and more people can clear it. Some brahmin kid gets a 89? Give him an A or die. 88? A, fine, whatever. 80%? Ok A minu.... ok ok A. A. A+++ AND A TROPHY WHATEVER, VERY GOOD SAAR.
Repeat that for a generation or two and even the most cowfuck ignorant of jeets gets a D- or C for a 35%, because the alternative is risking failing someone in a tribe that will kill the teacher and principal for it and replace them with their kinfolk who will pass them anyway.
Also remember, that's 33%... in Jeet culture. Cheating, bribes, nepotism, etc all mean you'd have to almost intentionally fuck up to fail. The only real conclusion is that their education system is basically nonexistent.