Cuba made fast progress restoring power to swaths of the Caribbean island nation on Tuesday, both in Havana and outlying provinces, even as emergency and grid workers struggled to reach areas ravaged by Tropical Storm Oscar.

Following three days of nationwide blackouts caused by the collapse of Cuba’s electrical system, power was restored to most of Havana on Monday, after Cuban authorities gave up efforts to restore the entire grid for now and opted to try to hook up individual regions around the country.