Problem
The United Nations Sustainable Development Goals focus on the human condition.
Without being an expert on the goals in general, identify one of the 17 goals and characterize that goal as being an "externality" in a standard Economic Supply and Demand context.
For Example ‚Just using the first SDG one, as an example - and for this question the answer cannot use this one explain how "Quality Education" is an externality solving issue. Presumably this means more education across the globe; yet the private market does not produce enough. The argument is that increasing education will have benefits not only to the individuals receiving it - but to society at large. In general we all benefit from educating more people. This externality is lost. This is the same logic, by the way, used by the State in funding education and we hear that from the Governor every year. With this it would be argued that there is a positive consumption externality for education, and yes, governments become involved to raise the bar shifting the demand curve for it out and also pushing the supply curve for it as well.
May likely have "better luck" finding an externality within one of the SD's dealing with pollution. Yes, a suggestion.