Arabic term (edited): العشوائيات

I believe you are asking for one word.

This is how *3ashwa2eyyat* is precisely expressed in English; "slums" or "slum areas", other expressions will sound poor to the English reader.

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This is from al-Ahram Weekly:
The original plan's objective was to stimulate economic development, to reduce population density in Cairo and to stem the growth of slum areas.
http://weekly.ahram.org.eg/2007/851/sc51.htm

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and this is from State information Service
الهيئة المصرية للاستعلامات
The new law will set regulations organizing urban planning to avoid any more slum areas, Nazif said.
http://www.sis.gov.eg/En/EgyptOnline/Economy/000009/02020000...