One day, my classmates and I rode bicycles across a river in Team Six. Just when we arrived nearby, there was an unbearable stench. As we approached, the stench became more pungent. Only then did I realize that the original culprit was the river. But why did this river become like this? No, I have to find out.

As a result, the river will become like this, usually because of pollution, but what is polluting the river? Where does pollution come from? In order to solve this puzzling mystery, I decided to explore it myself.

When I came to the river, I began to observe the surrounding environment. "Not bad!" "See the surrounding environment, I can't help but say. There is a large laundry processing factory by the river, opposite to the food factory and opposite to the orderly residential building. No problem! Just when I was thinking, suddenly the drain of the laundry processing factory next to me discharged dark water. Huh? Why is this water so dark? No treatment? Suddenly, a bag of unidentified objects flew out of a nearby residential building, only to see it somersault in the air like a diver, and then fell into the water with a loud noise, splashing several times. At this time, I finally realized that I understood everything. It turns out that the stink surge is formed like this.

At this time, I thought deeply. Those who are sleeping should wake up! If we throw rubbish into the river day after day and year after year, what will this river look like?