The air quality in downtown Cairo is more than 10 to 100 times of acceptable world standards. Cairo has a very poor dispersion factor because of lack of rain and its layout of tall buildings and narrow streets, which create a bowl like effect that traps pollutants. The main air pollution problem in Egypt is the particulate matter. The most notable sources of the dust and small particles is transportation, industry and open-air waste-burning. Another significant source is the wind blowing dust from dry arid areas into the city. The air in Egypt tends to be gray with a thick haze over Cairo. Two years ago when the Egyptian government began fully implementing taxis run on natural gas, there was much praise and fanfare. Air pollution was at monumental levels in the Egyptian capital Cairo and something was needed to curtail the growing problem that was leading to health hazards, including a dramatic rise in cases of asthma among young adults. While the country’s burgeoning taxis have largely made the switch to natural gas, congestion and poor maintenance continues to see air pollution one of the biggest problems facing everyday Egyptians.