This is the first year since 2015 that EM currencies as a group have depreciated by this much on a cumulative basis. A number of factors contributed to the recent sell-off. The most important one was probably the tightening in global financial conditions. Much has already been said about global policy tightening so I will not add to the debate here.
But to paraphrase Warren Buffett, the tightening of global financial conditions was synonymous with a tide that receded and revealed who was swimming naked.