The past few decades have seen a rising tide of people migrating from countries to big cities. While urban expansion may have some positive effects, the damage to the environment is much more serious. The main disadvantage of this trend is the increased possibility of environmental pollution. On the one hand ,The growing number of urban residents will generate more household waste than before. As a result, waste treatment will need burning and spilling, which will lead to more air pollution and soil degradation. On the other hand, People who moved to the city and have to go to work every day make more use of private cars, which greenhouse gas emissions would intensify air pollution and.worsen the ecological condition. Spaces tend to occupy the construction of homes and office buildings, which harms the urban ecosystem. The authorities could be argued to enjoy the influx of new immigrants, according to some. Environmental protection measures like the development of al...