Cuba restored power to most of Havana after a nationwide outage affected 10 million people. The grid collapse was triggered by a shorted transmission line. Oil-fired plants are back online, yet Cuba faces ongoing energy issues due to outdated infrastructure and geopolitical tensions.

Cuba has struggled with blackouts in recent months, including a nationwide one in December. Friday’s power failure was the fourth widespread one in five months. Government officials blame U.S. economic sanctions for the ongoing crisis, while others point to aging infrastructure, fuel shortages and the island’s susceptibility to hurricanes.

Electricity service in Cuba is gradually being restored more than 36 hours after a substation failure left the entire island in the dark.