GENEVA (Reuters) -Gaza's humanitarian catastrophe is deepening 20 months into Israel's war against Hamas, with conditions threatening to push nearly half a million people into famine by the end of September, according to U.N. estimates.

More than 57,000 people have been killed in the offensive, including over 500 in mass shootings while seeking food from distribution sites run by the U.S.-and Israeli-backed Gaza Humanitarian Foundation, according to Gaza health authorities.

The war was triggered in October 2023 when Hamas attacked Israel, killing 1,200 people and taking about 250 hostages, Israeli tallies show.

Here are some details of the humanitarian situation:

FOOD AND SUPPLIES

Israel cut off all supplies into Gaza from the beginning of March until late May, sharply worsening an acute shortage of food in the territory.

While some aid is allowed in, aid workers say it is not nearly enough and have issued warnings about fuel supplies running out, forcing shutdowns of incubators and ambulances.

More than 80% of Gaza's water wells and croplands, used to grow citrus and olives, have been destroyed in the war, according to the U.N. Food and Agricultural Organization (FAO).

A spokesperson for U.N. children's charity UNICEF last month described seeing Gazan children with signs of malnourishment, like exposed ribs, and the acute malnutrition rate has nearly tripled since a ceasefire earlier in 2025 when the aid flowed more freely.

There has not yet been a formal declaration of famine in Gaza by U.N. agencies: such a declaration hinges on a set of criteria measuring the extent of hunger suffered by a population and is assessed by the Integrated Food Security Phase Classification (IPC).

Still, nearly 500,000 people are facing catastrophic levels of food insecurity, which is the worst of the IPC's five phases of severity, and without urgent intervention they will be at risk of famine by the end of September, according to a report published in June by the FAO and World Food Programme. 

A further one million people, or close to half the population, are facing emergency levels of food insecurity.

Water scarcity is also a growing problem, with UNICEF warning that children may die of thirst.

AID DISTRIBUTION

An organisation backed by Israel and the United States called the Gaza Humanitarian Foundation began distributing food parcels at the end of May, overseeing a new aid model which the United Nations rejects.

Israel says the previous system had allowed Hamas militants to divert aid.

Hundreds have been killed near the GHF distribution hubs or along access roads guarded by Israeli forces, according to Palestinian medical authorities in the territory.

The GHF has defended its operations, saying it has delivered more than 52 million meals to needy Palestinians in five weeks. The Israeli military has said its forces opened fire on groups they viewed as a threat.

The United Nations says that more than half of its nearly 400 planned aid missions within Gaza in June were impeded or denied by Israeli authorities. 

DISPLACEMENT, SHELTER

Nearly all of Gaza's 2.3 million-strong population has been displaced by the war, with many uprooted several times.

Since March, the Israeli military has issued over 50 displacement orders and over 80% of the territory is now under such orders or within an Israeli-militarised zone, the U.N. says.

With people confined to ever-shrinking spaces, many have fled to sprawling tent cities on the beaches or among partially bombed buildings among millions of tons of rubble where they lack hygiene facilities and face risks from unexploded bombs.

Civilians sheltering in schools have frequently been killed, with Israel alleging such sites have been used by Hamas.

HEALTHCARE AND DISEASE

The World Health Organization describes the health sector in Gaza as being "on its knees", with shortages of fuel, medical supplies and frequent mass casualty influxes.

Only half of Gaza's 36 general hospitals are partially functioning and none are working in the north, a WHO spokesperson said.

There have been over 600 attacks on health facilities since the conflict began, the WHO says, without attributing blame.

Poor hygiene and living conditions are creating ideal conditions for the spread of disease, with the WHO reporting a rise in meningitis cases in children in recent weeks.

The WHO is helping to evacuate Gazans who cannot get the specialised care they need within the enclave, but around 10,000 people remain on the waiting list, it says.

(Compiled by Emma Farge; Editing by William Maclean)