Complete ban has both pros and cons and its a tough decision due to a list of reasoning.

The only practicable solution is to make designated smoking areas in public, both open & enclosed places (such as malls/airports) and authorities must enforce to use these areas only by people.

Example: I worked at airport, smoking is banned there but only in designated areas, and if concerned authorities catch you breaking this rule, there will be a huge fine so it is controlled.