After spewing steam, molten lava and ash on July 4 and 5, Popocatepetl, the active volcano 65 miles east of Mexico City, simmered down on July 8, although experts were keeping close watch on its activity.
Six U.S. airlines canceled more than 45 flights to and from the airports in Mexico City and nearby Toluca on July 4 and 5, although the airports themselves never closed. Ash from El Popo drifted over large parts of Mexico City.
Experts said the activity took place as a new dome of lava formed inside the crater.
No evacuations in the vicinity of the volcano have been ordered.