Normally all education institutions at the level of university have some student bodies that work for the facilitation of student life at campus by arranging social events, finding discounts, job fairs, networking students with professional bodies and also help students in many other ways so as to make for a pleasant experience. These unions have nothing to do with external politics.
But in Pakistan everything is topsy turvy and the same is true of the student unions. In Pakistan, student unions are wings of political and religious parties and their aim is to use students for their political agendas and thus creating an environment that is totally non-conducive to studies. Even worse, these organisation are often involved in a lot of criminal activities e.g. strikes at campus, fighting and even killing the opposing and dissenting people including students and even teachers. These are mafias that have permeated a lot govt educational institutions and somehow the ruling elite easily overlooks this problem partly because they themselves create and benefit from these organisation but also because their own children study abroad.