By Donald G. McNeil Jr. June 23, 2020

As the coronavirus pandemic hits more impoverished countries with fragile health care systems, global health authorities are scrambling for supplies of a simple treatment that saves lives: oxygen.

Many patients severely ill with Covid-19, the illness caused by the coronavirus, require help with breathing at some point. But now the epidemic is spreading rapidly in South Asia, Latin America and parts of Africa, regions of the world where many hospitals are poorly equipped and lack the ventilators, tanks and other equipment necessary to save patients whose lungs are failing.

The World Health Organization is hoping to raise $250 million to increase oxygen delivery to those regions. The World Bank and the African Union are contributing to the effort, and some medical charities are seeking donations for the cause.

The W.H.O. estimated on Wednesday that with about one million new coronavirus cases worldwide per week, the world will need 620,000 cubic meters of oxygen per day, or 88,000 large cylinders.

By a stroke of luck, the W.H.O., UNICEF and the Bill & Melinda Gates Foundation in 2017 began searching for ways to increase oxygen delivery in poor and middle-income countries — not in anticipation of a pandemic, but because oxygen can save the lives of premature infants and children with pneumonia.

The organizations began ordering equipment in January, but within weeks suppliers were swamped by the sudden surge in demand created by the pandemic.