IELTS Grammar: conditional mistakes

Can you correct the mistakes in the following conditional sentences?

1. If there was a ban on cigarette, less people would smoke cigarette.
2. If the tax rate on junk food had increased, people would likely to prefer making food at home.
3. If schools administered with any teachers, disorder and lawlessness would arise.
4. If uncensored commercials had been banned, the crime rate would be seized from rising.