A nationwide blackout struck Ecuador on Wednesday, affecting its 18 million residents.

Energy Minister Roberto Luque attributed the outage to an issue with a southern transmission line, which caused a “cascading disconnection.”

This was the first major blackout in 20 years, highlighting the country’s fragile energy system and ongoing energy crisis, according to Luque.

By 7 p.m. local time, 95% of the power was restored, with full service expected by midnight.

The blackout also halted the recently inaugurated subway in Quito, despite its independent backup power supply.

Earlier this year, Ecuador experienced rolling blackouts due to severe drought, and recent heavy rains led to the shutdown of the nation’s largest hydroelectric plant and a major pipeline, Bloomberg has reported.

Luque stated that the blackout could have been avoided with proper investment and maintenance of transmission lines.

He also noted that plans to prevent such incidents were developed 20 years ago but never implemented.

Written by B.C. Begley