If the drainage works are not in place, a similar situation will generally occur after the rain.
Of course, it does not rule out that nearby construction will lead to serious water pollution, such as overflow, pipeline transportation, soil infiltration, etc., which will lead to muddy water.
Your so-called "green"? It may be the phenomenon of eutrophication-too much domestic sewage and organic factory sewage are discharged into the water body.
If there are photos or images, it will be much more convenient to judge.
When filling in the college entrance examination, what is the major of in