Let the government legalise prostitution and then tax it highly and use the revenue to improve other sectors. Maybe the high taxes will deter the practice.
Sex trade has not just started now. It started millions of years ago. Many women are jobless. The few who open up businesses and vend their goods on streets are arrested and their goods taken by KCCA. Now, what do you want them to do? They also have needs like accommodation, feeding, etc. The rich people, especially in leadership, do not even care about the poor majority and the gap is increasing day by day. So the only alternative for most of these women is to sell sex for survival.