By the end of the first quarter of the XXI century. according to one of the UN forecasts, annual urban population growth in developing countries will amount to approximately 90 million people. This leads to the absorption of agricultural land by cities. But it is in most developing countries, where often (especially in Africa), part of the urban population is engaged in agriculture, that the growing shortage of agricultural land is especially painful. Such a "sprawl" of cities also worsens the environmental conditions of urban areas in developing countries. An important effect on the state of the environment is provided by the surface arrangement in the areas of their location. This, in particular, is shown by the examples of a number of large centers in Latin America. Many of them are located high in the mountains. They are surrounded by mountain ranges, which complicates the natural ventilation of the air basin and the removal of pollutants. In addition, in high-altitude agglomerations, where a significant part of the population of Mexico, Central America and the Andean countries is concentrated, incomplete combustion of fuel occurs due to rarefied air. For this reason, compared with flat cities, air emissions increase: carbon monoxide by 60%, nitrogen oxide by 50%. For the capital of Mexico, the petrochemical smog was a real disaster - dry creeping and smoky fog. "Smog" often lasts for several days and causes great harm to the health of the population of the Mexican metropolitan area.
The environmental conditions of cities in developing countries are affected by the weakness of water management and limited water supply. It is characteristic that in most of them the water consumption per inhabitant is only slightly higher than the biologically necessary level. Moreover, water quality, as a rule, does not meet international standards. This is often also characteristic of areas with significant water resources. Even in Latin America, where water management is at a higher level than other regions in developing countries, only about 2/3 of the urban population is provided with water from special networks. But water quality is often low due to various contaminants.
By the end of the first quarter of the XXI century. according to one of the UN forecasts, annual urban population growth in developing countries will amount to approximately 90 million people. This leads to the absorption of agricultural land by cities. But it is in most developing countries, where often (especially in Africa), part of the urban population is engaged in agriculture, that the growing shortage of agricultural land is especially painful. Such a "sprawl" of cities also worsens the environmental conditions of urban areas in developing countries. An important effect on the state of the environment is provided by the surface arrangement in the areas of their location. This, in particular, is shown by the examples of a number of large centers in Latin America. Many of them are located high in the mountains. They are surrounded by mountain ranges, which complicates the natural ventilation of the air basin and the removal of pollutants. In addition, in high-altitude agglomerations, where a significant part of the population of Mexico, Central America and the Andean countries is concentrated, incomplete combustion of fuel occurs due to rarefied air. For this reason, compared with flat cities, air emissions increase: carbon monoxide by 60%, nitrogen oxide by 50%. For the capital of Mexico, the petrochemical smog was a real disaster - dry creeping and smoky fog. "Smog" often lasts for several days and causes great harm to the health of the population of the Mexican metropolitan area.
The environmental conditions of cities in developing countries are affected by the weakness of water management and limited water supply. It is characteristic that in most of them the water consumption per inhabitant is only slightly higher than the biologically necessary level. Moreover, water quality, as a rule, does not meet international standards. This is often also characteristic of areas with significant water resources. Even in Latin America, where water management is at a higher level than other regions in developing countries, only about 2/3 of the urban population is provided with water from special networks. But water quality is often low due to various contaminants.