Due to mass migration from impoverished rural districts wracked with political instability, Guatemala City's population has exploded since the 1970s, severely straining the existing bureaucratic and physical infrastructure of the city. As a result, chronic traffic congestion, shortages of safe potable water in some areas of the city, and a sudden and prolonged surge in crime have become perennial problems. The infrastructure, although continuing to grow and improve in some areas, it is lagging in relation to the increasing population of those less fortunate.