[Developing countries] For children in developing countries the situation is particularly alarming. The mortality rate may be more than 50 times that in developed countries. These were the conclusions of WHO, drawn from analyses of mortality and case fatality from acute respiratory infections in children under five years of age in nearly all the countries of the Americas and Southeast Asia and in several countries in the African and the western Pacific. It is a result of low birth weight, very young ages of mothers and births following too closely upon one another, malnutrition, lack of breast-feeding, indoor air pollution stemming from burning of 'biomass' fuel and exposure to 'passive smoking' at home.