Please correct and comment my summary about overpopulation

Over the past century, there has been a dramatic increase in the number of people in big cities, leading to a variety of negative effects on people's lives. The most important one is unemployment, which is a direct influence of the rise in the urban population. Nowadays, that the number of people who lacking jobs increases intensely. Due to over-crowding, there are not enough available jobs for all of them. China can be considered as a typical example of overpopulation, where usually encounters a high number of jobless people. The second major consequence which results from the density of population is the shortage of accommodation. The more people live in one place, the more lands they need. Unfortunately, many people are unable to find a place to live in, which is a step back for cities' development. That is the reason why more and more slums are appearing now. Finally, traffic jams are also believed to be caused in over-crowded areas. In most of the countries, drivers have to face congestion in peak hours very long in order to move. Not only does overpopulation result in congestion but the smoke and emission from vehicles also have bad impacts on people's health. To sum up, so many bad effects does overpopulation create that government and individuals need to take urgent actions to tackle this uncontrollable growth of the population.