A man walks in fog at Maksimir Park in Zagreb, Croatia, on Jan. 13, 2020. Low temperatures and heavy fog hit parts of Croatia this week. Photo:Xinhua

Frosted leaves are seen in Zagreb, Croatia, on Jan. 14, 2020. Low temperatures and heavy fog hit parts of Croatia this week. Photo:Xinhua

A woman walks in fog in Zagreb, Croatia, on Jan. 14, 2020. Low temperatures and heavy fog hit parts of Croatia this week. Photo:Xinhua

A building is shrouded in fog at Maksimir Park in Zagreb, Croatia, on Jan. 13, 2020. Low temperatures and heavy fog hit parts of Croatia this week. Photo:Xinhua

Frosted leaves are seen in Zagreb, Croatia, on Jan. 13, 2020. Low temperatures and heavy fog hit parts of Croatia this week. Photo:Xinhua