ISIL (Islamic State in Iraq and the Levant) has taken control of three major cities and the results have been unpleasant and expected. In 2014 they took the eastern Syria city of Raqqa (population 500,000) and turned it into an “Islamic city.” Strict lifestyle rules were imposed and local Christians have to pay an extra tax to avoid persecution. Then, in mid-2014 they took Mosul (two million) in Iraq. In May 2015 they took Ramadi (200,000). All three cities already had problems with electricity and water supplies and shaky sewage systems. Many of the inhabitants of these cities fled, although that became more difficult once armed ISIL men were patrolling the streets and controlling the roads in and out of town. In Ramadi more than half the population was gone when ISIL arrived and that was largely because it was now well known what would happen when ISIL took over. In short, nothing good.
ISIL enforces the strictest lifestyle rules, based on an interpretation of Islamic scripture that is more hostile to most modern tech than al Qaeda ever was. That means no music, video or anything that can be identified as “Western.” Exceptions are made, grudgingly, when it is necessary to keep ISIL members alive. Thus while Western aid groups are banned, Western medical supplies are allowed in but ISIL members get priority. Even Moslem medical personnel must prove there are Islamic enough to meet ISIL standards. Those who cannot, and that means most of them, are threatened. Some are killed but the rest flee. The few medical personnel who remain can barely care for ISIL leadership and some combat wounds.
Getting electricity, water and sanitation networks operating is a priority but crippled by lack of supplies (especially fuel) and spare parts as well as people qualified to repair and operate things. Anywhere else in the Middle East foreign suppliers and experts would be called upon as necessary. That is not Islamic according to ISIL and instead locals with some skills to step forward and try to cope. The result is intermittent water supplies, unreliable sanitation systems and lots of people using portable generators for power or living in the dark.
Many of the civilians who stayed behind have managed to adapt and an economy of sorts has been created. In late 2014 ISIL sought to create their own currency (gold coins) but that did not get far. So any currency (local, Western) that works is used. “Taxes” are collected in a medieval fashion that could best be described (in modern terms) as opportunistic extortion. This begins with lots of looting when ISIL takes control of new territory. While much is made of Moslems (especially Western ones) trying to get to get to the Islamic State the reality is that more people already there are trying to get out. In many cases this is a matter of life and death because the collapse of the medical care system has left most people with few useful options if they get sick or injured. ISIL considers such misfortunes “the will of God” and complainers are regarded as heretics.