... (d) Any
work or
service exacted in
cases of
emergency, that is to say,
in the
event of
war or of a
calamity or threatened
calamity, such as
fire,
flood, famine,
earthquake, violent
epidemic or epizootic
diseases,
invasion by
animal, insect or vegetable pests, and in
general any
circumstance that would
endanger the existence or the
well-being of the
whole or part of the
population; ...