Complex sentence: On this day after being held over Lagos, the flight continued directly to Abidjan because of poor local weather conditions: harmattan winds blowing southwards from the Sahara made skies over Lagos unusually hazy on that day, and all incoming flights at Lagos Airport were halted.
Split into simpler sentences: On this day, after being held over Lagos, the flight continued directly to Abidjan because of poor local weather conditions. More specifically, harmattan winds blowing southwards from the Sahara made skies over Lagos unusually hazy on that day, and all incoming flights at Lagos Airport were halted.