In London around 11am the march assembles on Camberwell Green. About 250 people are here, from many parts of Britain; I meet marchers from Newcastle, Manchester, Leicester, and especially organized-labor stronghold Sheffield. The sky is grey but the atmosphere is convivial; five members of London's Metropolitan Police are present, and they're all smiling. Most marchers are young, some as young as high school age, but a few are older; some teachers, including members of the Lewisham and Sheffield chapters of the National Union of Teachers, are carrying banners in support of their students.

Can we draw the following conclusion?
The sky is not blue.
Yes