CENAPRED reported that each day during 20-26 May there were 90-251 steam-and-gas emissions from Popocatépetl, some of which contained minor amounts of ash.
The plumes drifted mainly E and SE.
An explosion at 0302 on 21 May ejected incandescent material onto the flanks.
The Alert Level remained at Yellow, Phase Two (middle level on a three-color scale).
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)