We have explored the problem. If you had started with the solution you must work back to figure out what your business is solving. This might take some time. You may even figure out that you are solving an entirely different problem than that you had assumed.
A solution is a theory of how to eradicate the problem. However, there is rarely one solution to a problem. Let us take garbage collection/ garbage clean up in the CBD. One solution is to clean after people as they litter. So you can hire people to walk around and sweep all day. Another solution is to provide dust bins in appropriate locations. This way people can throw their trash. Another alternative is to create awareness. Teach people the risks of throwing garbage everywhere. There are many ways you can create awareness e.g create a sense of ownership, put laws to deter people i.e fines etc. There are many alternatives as you can see.