聚众滋事

yǔ wǒ men xiān qián chún jìng de xiào yuán xiāng bǐ zhū rú jù zhòng zī shì děng xiàn xiàng yǐ bù hǎn jiàn

与我们先前纯净的校园相比，诸如聚众滋事等现象已不罕见。

It is not rare to see such things as mob fights, which are eroding our formerly pure campuses.