Individual schools in northern France will remain closed on Monday due to flooding, the Pas-de-Calais prefecture announced on Friday. It said that 13 institutions would not be able to receive pupils at the start of school after the Christmas holidays on Monday. Some lessons will be held elsewhere and some online. Heavy rain had caused several rivers in the area to overflow. The Pas-de-Calais region is now only on the second-highest orange warning level. More than 700 people had to leave their homes due to the flooding. Around 250 people still have no electricity, according to the prefecture. N…