How is "civilian infrastructure" defined in international humanitarian law?

Question

The Houthi forces of Yemen have launched a drone attack on oil facilities and the airport in Abu Dhabi, capital of the United Arab Emirates. UN Secretary-General Antonio Guterres condemned the strike, saying:

attacks on civilians and civilian infrastructure are prohibited by international humanitarian law.

This appears to be saying that the attacks were against international law because of the nature of the targets. However, airports are generally the first target of any military operation against a country, and oil facilities have been high on the list of targets in warfare since the internal combustion engine has been a weapon of war. In response the coalition has carried out air raids in the Yemeni capital Sanaa, killing more than 12 people and pictures apparently showing damaged residential buildings. This has elicited no such claims of breach of international humanitarian law.

How is "civilian infrastructure" defined in international humanitarian law? Is it a reasonable interpretation that this would include oil production facilities and an airport but not residential buildings?

Answer 1

Everything that isn’t a military objective is civilian

Legal definitions don’t come much simpler than that. I guess you won’t be satisfied until you get the definition of a military objective though?

Fortunately, the International Committee of the Red Cross maintains a database of customary international law including all the international instruments, the national laws that implement them and the relevant case law.

Rule 8 contains the definitions from each instrument which are very similar so I will quote just one:

“Military objective” means, so far as objects are concerned, any object which by its nature, location, purpose or use makes an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage.

Specifically with reference to air attack:

Article 24(1) of the 1923 Hague Rules of Air Warfare provides: “Aerial bombardment is legitimate only when directed at a military objective, that is to say, an object of which the destruction or injury would constitute a distinct military advantage to the belligerent.”

An airport and fuel storage that was exclusively used for commercial aviation is not, prima facie a military objective which makes it civilian. However, if the attacker possessed reasonable intelligence that the airport or fuel was or world shortly be repurposed for military activities, then it would be a military objective.