Russia’s once-dominant gas supply to Europe via Ukraine, which flowed for decades, is set to end on New Year’s Day with the collapse of a contract between the two warring countries that paid out billions to Moscow in gas revenue and to Kyiv in transit fees.

A transnational pipeline was shut down on Wednesday after Kyiv refused to renew a prewar agreement that allowed for the transit of Russian gas through its territory.

The gas supply was halted by Ukraine, which collected transit fees while a Russian state-owned energy giant earned money from the supply.