In the world, the pollution level in large cities is being worse. What are the causes and solutions?

In these days and age, the contamination degree in major urban places is becoming serious. Some understandable causes related to this phenomenon and several effective solutions could be taken to address this problem. On the one hand, two primary reasons could explain why this could be the case. Firstly, by virtue of the proliferation of industrial zones in major metropolises, factories have been discharging chemical waste into rivers and oceans, which in turn leads to a substantial increase in the pollution of water bodies. Besides, toxic gas emissions derived from industrialized factories had also made a great contribution to air degradation. Secondly, the number of private vehicles such as motorbikes and cars are rising at an unprecedented rate, which means the atmosphere would be enormously contaminated by emission released from those transports. To be more specific, people's living standards in urban areas are getting higher and therefore they have more desire to purchase for such vehicles. Nonetheless, some fruitful measures should be taken into serious consideration by both governments and individuals. In terms of authorities, the national leader must force companies to establish a waste treatment system in an attempt to reduce the pollutants. As a result, the environment would be significantly improved. Those who have no desire to follow the government's rules should be held accountable and fined severely if firms had no desire to undertake that policy, regardless of how large or small they are. Regarding the citizens, they should take public transport rather than driving their private vehicles regularly. In this way, it not solely helps them to save a considerable amount of money, but the natural world would be also immensely strengthened. In conclusion, despite some factors that can lead to environmental problems in large cities, numerous steps can solve this issue.