More importantly, this superimposing governmental levels combined with the fact that the MABA lies on a flat terrain with relatively good ventilation has been an excuse for a relatively poor air quality management in this highly populated urban zone, which lacks an official inventory of emissions of mobile sources. In addition, the availability of local and process-specific information on emissions represents a serious data gap, a common feature of many cities in developing countries (Guttikunda et al., 2005).