"It was the sound of distress: crying, howling, whimpering and moaning. At any one time a large proportion of the servants were suffering nalka"
Nalka is the physical pain suffered by lovers upon being separated from each other. It usually manifests about ten days after their last engagement in sexual intercourse and is complete within four days of the first pains.
The affliction is usually fatal to those who suffer it before the age of twenty, and so it is not advised that lovers enter into a sexual relationship before they're old enough to withstand it.
It represents the termination of the bond between partners and their potential to procreate. However, lovers are able to have children subsequently, but only if they are able to maintain a sexual relationship without undergoing nalka for nine years.