KARACHI, Pakistan (AP) — On the outskirts of the slums of Pakistan’s biggest city, protesters burning tires and throwing stones have what sounds like a simple demand: They want water at least once a week.

But that’s anything but in Karachi, where people go days without getting water from city trucks, sometimes forcing them to use groundwater contaminated with salt. A recent drought has only made the problem worse. And as the city of roughly 18 million people rapidly grows, the water shortages are only expected to get worse.