People in the north of Senegal usually wear long, robes to protect themselves from the sun and sand.

People in northern Senegal usually wear long light-colored robes and stiff fabrics to protect themselves from the sun and sand.

Explanation:

Senegalese are subject to dangerous temperatures and radiation for their skin, that is why the fabrics they use cover almost the entire body, they are not very porous for the sand to pierce and hurt them, and light colors to absorb the least radiation possible solar.