Many megalopolises and big cities are known for their high levels of air pollution, which cause serious illnesses and even premature death for city residents. This essay will discuss the principal reasons for bad air quality in cities and how this problem can be tackled. Urban pollution today is generated by several sources, with the single largest cause being vehicles. Today millions of cars crowd the narrow city streets. As a result, the poisonous particles emitted by the cars’ diesel and petrol engines become trapped between tall buildings, causing the pollution levels to accumulate. Some of the pollution is also produced by domestic sources –such as heating systems – and manufacturing, though their contribution is usually significantly smaller. From my perspective, the most obvious approach to clean up city air is to fight the biggest polluter — private cars. In order to reduce their numbers, two main policies may be required. The first one is improving public transport. If bus...