Evergrande is basically a large ponzi scheme where they kept taking out loans to keep themselves afloat, this was due to the kickbacks given to the person offering the loans so you get a billion loan and give back 100million to the guy who gave you the loan. Also the group behind Evergrande is an enemy of Xi Jinping so he stopped them from being able to keep the ponzi going and is instead letting them all go bankrupt, its also the reason china is preventing people using crypto so they cannot take their wealth outside the country.