This isn’t the first time the Mexico volcano, Popocatépetl, has spewed ash and smoke. Still, the last week has been especially concerning as enough ash fell to close the region’s two airports and public schools over the weekend.

Around 25 million people live within a 62-mile radius of the base of the volcano, per The Associated Press. This includes parts of Mexico City, located northwest of the volcano, and a region called Puebla, to the east.

“El Popo,” as locals call it, has been more or less active since it first reawakened in 1994, reported AP. Some locals have seemingly learned to live with its temper tantrums that spew rocks, ash and fumes, while others are a bit unnerved by the building activity and its implications on crops, animals and children.

“You can see (the volcano) doesn’t want to be OK anymore,” Violeta Fuentes, who lives near the base with her husband and two children, told AP.

In a three-level system, a team of scientists watching the volcano from Mexico City let residents know how safe the area is — green for good to go, yellow for an alert, or red for danger, per AP. It remains on yellow for now but has risen to phase 3, even closer to evacuation.

Mexico’s National Center of Disaster Prevention shared a video of Popocatépetl’s activity, throwing smoke and debris in the air from Monday.

Officials are encouraging residents to stay indoors as much as possible, and have closed public areas as of Monday, reported The New York Times. Evacuation drills were run and temporary shelters were put into place.

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