From the article:

On February 18th the World Health Organisation (who) said the Nasser hospital in Khan Younis … was no longer functional. … After more than four months of war, only a quarter of Gaza’s 36 hospitals and less than a third of its 72 health clinics are operating—and those only partially.

Gaza’s health system is being destroyed at its roots. Health-workers are exhausted and traumatised, ambulances have been wrecked and the hospitals still standing may be structurally unstable.

Israel says Gaza’s hospitals are legitimate targets. It has published evidence that it says shows that Hamas fighters have hidden among patients and stored weapons in at least a few hospitals. … Israel has not allowed independent investigators to access the hospitals and verify the allegations.

First heard about this on The Economist podcast, The Intelligence.