In this case it probably means at different institutional levels: at the level of the city government, the federal or national government, and at the level of local law enforcement. The phrase "on many levels" is also used to mean simply "in many ways," which could also apply here. For example, using many different methods to end child labor, such as enacting stricter laws, educating people about the effects of child labor, etec.

Hi Salvater In this sentence "on many levels" is referring to levels of society. So for example in order to end child labour action will need to be taken by the government but also by businesses and citizens in order to make a change. I hope that helps! :)

Means that help will be required from a lot of leaders from several groups. One person or group can't solve this problem, it's complexity needs mass cooperation