Answer:
There are many problems of urbanization but to name 3 those would be bad infrastructure, flooding and crime rates.
Many cities were not pre-planned but they just expanded over time. So this means that nobody planned ahead and many roads are not very well organized, in many cities during heavy rainfall there are floods since the drainage system is not well planned out to handle a flood and in high-density areas, there is higher crime rate. More people means more crime generally.