In the end of 1987, Nest Lake City built a garbage disposal site in a few kilometers away from the city, and many villagers welcomed it as the only garbage disposal site when it could be fertilized. After a decade, the population of Nest Lake City was less than 100,000, the population of Nest Lake City doubled, the amount of garbage produced per day was about 30 to 400 tons, and the danger to the environment was not clear at a time, and then everyone was not aware of the waste disposal and therefore did not take the garbage field as a matter, and the villagers in the vicinity were still welcomed as the garbage disposal site, because the people in the city could be fertilized. After a decade, the population of Nest Lake City doubled, the amount of garbage produced per day was 300