Related Rule
Ukraine
Practice Relating to Rule 70. Weapons of a Nature to Cause Superfluous Injury or Unnecessary Suffering
Ukraine’s IHL Manual (2004) states:
Prohibitions and limitations on the choice of methods and means of warfare for the belligerents are set forth in order to avoid unnecessary suffering and unjustifiable casualties among the civilian population, [and] infliction of severe and long-term damage to the natural environment related to warfare. 
Ukraine, Manual on the Application of IHL Rules, Ministry of Defence, 11 September 2004, § 1.3.1.