After three years of unprecedented drought, a South African city with four million people -- Cape Town -- has only about 80 days worth of water in its reservoirs. It could become the world's first major city to run out of water, unless residents drastically cut daily use. The risk is real and requires voluntary reductions that aren't being widely taken yet, Mayor Patricia De Lille and other officials warn. "It is quite unbelievable that a majority of people do not seem to care and are sending all of us headlong towards Day Zero," the provincial government says, using a phrase for April 21 – the projected date when only essential sites like hospitals and schools will get tap water.

Soon, high fees may be imposed for use above certain levels. Cape Town won't literally run dry because the last 10 percent of each reservoir’s water is unusable due to silt and other debris. So when the dams drop below 14 percent of capacity, water flow will be turned off for all but a few exempt sites. Families then will have to fill jugs at 200 distribution centers, with a daily limit of 25 liters (6.6 gallons) per person. Those who can afford it will buy deliveries from less-affected parts of South Africa, as companies already advertise.

The emergency, which might last until the rainy season begins in May, is watched worldwide by scientists and city managers who also worry about growing populations and shrinking resources. Cape Town hasn't kept up with a population that has nearly doubled over the past 20 years. In addition, University of Cape Town scientists say, similar droughts could be more common because of global warming. In a costly rush to catch up, the city is building plants to remove salt from seawater and is considering wells to extract groundwater. But those future remedies won't be ready by late April.

Resident says: "There are a lot of people who have been in denial and now they suddenly realize this is for real." -- Shirley Curry

Government says: "We have reached a point of no return. The chance of reaching Day Zero on 21 April 2018 is now very likely. . . . The time to act for everyone's sake is now." – Jan. 18 statement from Western Cape Province

Journalist writes: "Climate change researchers predict more frequent dry years and fewer wet years to come. Cape Town is likely just getting a preview of the new normal." – Aryn Baker, Time magazine