breeding ground

noun
1
a place where wild animals go to produce their young
محل زادآوری, محل زاد و ولد, زیستگاه تولید مثل
2
a place where something, especially something bad, is able to develop
محل پرورش, زمینه رشد, بستر, خاستگاه, زمین مساعد, محل رشد
This area of the city has become a breeding ground for violent crime.