Mexico's National Center for Disaster Prevention reported there had been three explosive eruptions at the peak late Friday and early Saturday — events that usually toss glowing-hot rock on the volcano's flanks. It said that Popocatepetl has also continuously spewed clouds of ash into the air, most of which was headed northwest, toward Mexico City.
U.S. airlines canceled at least one flight at Mexico City's airport on Friday as a precautionary measure, though airport authorities said the terminal was fully able to operate. Alaska Airlines had cancelled its route to Los Angeles, the airport press office said in its Twitter account.
On Friday, four airlines cancelled a total of 17 flights "due to climate conditions and in accordance with their own internal policies," the airport said in a statement.
The volcano is about 40 miles (65 kilometers) from the airport, which is in turn a few miles east of the city's center.
The Environment Ministry has urged residents to take preventive measures to deal with the ash, including wearing dust masks, covering water supplies and staying indoors as needed.
Mexico City authorities recommend that people sweep up any ash and put it plastic bags to keep it from mixing with water and forming a concrete-like substance that can block drains.