It turns out that the level is lacking the lights of the first three sefirot, since on account of the ascent of Malkhut to Bina the level is cleaved into two halves: Half of it remains in the level, namely the vessels Keter and Ḥokhma and the lights ruaḥ and nefesh, while half of it left the level, specifically the vessels Bina, Tiferet, and Malkhut and the lights neshama, ḥaya, and yeḥida.
Therefore, this ascent of Malkhut to Bina is alluded to through the mystical meaning of the yod that enters the or, light (spelled alef-vav-resh) of the level, so that or becomes avir, air (spelled alef-vav-yod-resh). Due to the ascent of the Malkhut to Bina, the level lost the light of its first three sefirot and remained at the height of ruaḥ and nefesh, which is called air (as explained in Zohar, Bereshit 1:32, and in the Sulam there, s.v. “beka”).