A street gang is a small or very large loosely organized group of criminals.they often “claim turfs” or neighborhoods which they use to put up sell drugs,guns,other illegal things etc. Street gangs will often name their gang after its street or neighborhood ex: Eastside Fruities,Almighty forest pines fags. The modern gangs we see nowadays started in Los Angeles California with the crips in late 1960s-70s (Chicago gangs also helped create gangs that we see today). Gangs will often engage in conflict (also called gang wars) in which they fight each other with weapons from switchblades to shotguns and assault rifles. Notable gangs:

Latin Kings,crips,bloods,ABZ,Surenos,notterenos,ms13,202,Folk nation,people nation,MLD,imperial gangsters,Spanish cobras,Latin dragons,.

"allow it" means to just leave something alone, or don't worry about it. People in West London say this quite often.