Ash spewing from the Popocatepetl volcano outside Mexico City on Tuesday led some airlines to cancel around two dozen flights in and out of the Latin American capital, authorities said.
The Mexico City International Airport said on social media that national and international operators have canceled 22 flights "due to airplane safety checks having found ashes."
The airport's arrivals and departures log, seen by AFP, showed cancellations and delays, though the causes weren't listed.
Authorities have warned ash is likely to fall in the states of Morelos, Puebla and Mexico, as well as in Mexico City, which lies some 55 miles (90 kilometers) from the volcano.
A plane is seen at the Benito Juarez International Airport in Mexico City. AFP
Since Popocatepetl became active in December 1994, after six decades of quiet, ascents have been prohibited, a hostel for mountaineers was closed and access near the crater has been restricted.
It has seen increased activity ever since, and occasionally it has been necessary to evacuate residents of nearby rural communities.
Nerves were rattled when spewed ashes, gases and molten rock in May of last year.
Some 25 million people live within a 60-mile radius of the volcano, making it among the most dangerous in the world, though it has not had a massive eruption in more than a millennium.
Agence France-Presse