HOUSTON — The agreement by major oil producers on Sunday to reduce their daily production by 9.7 million barrels was the largest cutback in history and a feat of remarkable coordination by more than 20 nations led by Saudi Arabia and Russia with unusual mediation from the United States.

But it probably still won’t be enough.

Demand for oil has tumbled in recent weeks as the coronavirus pandemic has crippled global commerce and eliminated untold numbers of commutes, plane trips and cargo shipments. Experts estimate that demand has fallen by somewhere between 25 million barrels and 35 million barrels a day — or up to three and a half times as much as what the oil nations are promising to cut.

News of the deal briefly lifted oil prices on Monday, but those gains faded over the course of the day. The U.S. oil price benchmark ended the day at $22.41, or less than half of where it was at the start of the year. Had the group of oil-producing nations, known as OPEC Plus, not reached a deal, oil prices would have collapsed, industry experts said.

Leaders of the American oil industry, which is responsible directly and indirectly for roughly 10 million jobs, welcomed the deal and President Trump’s role in mediating a halt to a Saudi-Russian price war. But even they acknowledged that it would not end their financial difficulties.