Related Rule
Practice Relating to Rule 9. Definition of Civilian Objects
Mexico’s IHL Guidelines (2009) states: “A civilian object is any object (a community, its facilities and personal property) which is not a military objective and which by its nature, location, purpose or use does not contribute to forming a military objective.” 
Mexico, Cartilla de Derecho Internacional Humanitario, Ministry of National Defence, 2009, § 2.
At the CDDH, Mexico stated that it believed Article 47 of the draft Additional Protocol I (now Article 52) to be so essential that it “cannot be the subject of any reservations whatsoever since these would be inconsistent with the aim and purpose of Protocol I and undermine its basis”. 
Mexico, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.41, 26 May 1977, p. 193.