A/HRC/37/58 immune systems are still developing, they are at higher risk of respiratory infections and have less ability to combat them.9 17. Ambient air pollution mainly results from factories and vehicles, and household air pollution comes primarily from the use of wood, coal and other solid fuels for cooking and heating. The vast majority of children — about 2 billion — live in areas that exceed the WHO ambient standard for particulate matter, and 300 million children live in areas whose ambient air pollution exceeds international standards by six times or more. 10 Over 1 billion children around the world live in homes that use solid fuels for cooking and heating.11 WHO has estimated that together, ambient and household air pollution cause more than one half of all lower respiratory infections, such as pneumonia and bronchitis, in children under 5 in low- and middle-income countries, and that lower respiratory infections accounted for 15.5 per cent of deaths of all children under the age of 5 in 2015. 12 18. Children who survive early exposure to air pollution can still suffer from it throughout their lives: it can disrupt their physical and cognitive development and make them more prone to lung cancer, asthma, other respiratory diseases and cardiovascular diseases.13 The harm from air pollution begins before birth. As the Special Rapporteur on hazardous substances and wastes has said, children are often born “pre-polluted” because of their mothers’ exposure to pollutants during pregnancy, which is associated with preterm delivery, lower birthweight and early fetal loss (see A/HRC/33/41, paras. 5 and 16). 14 2. Water pollution 19. Water pollution resulting primarily from unsafe sanitation practices contributes to diarrhoeal diseases that cause more than 350,000 deaths a year of children under 5 years old, and another 80,000 deaths of children aged 5 to 14. 15 Water pollution also contributes to intestinal and parasitic infections such as schistosomiasis, which gravely affect the physical and cognitive development of children.16 These infections, as well as diarrhoea, impair the proper functioning of the digestive system and prevent the absorption of nutrients essential for growth and development. 17 Lack of access to safe water also increases the incidence of other diseases, including trachoma, the main preventable cause of blindness. 18 More generally, unsafe water contributes to food insecurity, malnutrition and stunting of children.19 UNICEF stated in 2013 that approximately 165 million children under 5 suffer from stunting as a result of inadequate nutrition and unhealthy water and sanitation. 20 Stunted children are not only shorter than they should be for their age; they suffer harm throughout their lives, including weaker immune systems and reduced brain development. 20. Children are particularly at risk from water pollution, like air pollution, because their bodies are still developing. In addition, they drink more water than adults in relation to their body weight, and they absorb a greater proportion of some waterborne chemicals. 21 9 10 11 12 13 14 15 16 17 18 19 20 21 6 Ibid., pp. 9 and 40. Ibid., pp. 8 and 60. Ibid., p. 9. WHO, “Don’t pollute my future!”, pp. 2–3. UNICEF, Clear the air for children, pp. 29–32; WHO, “Don’t pollute my future!”, p. 8. See also UNICEF, Clear the air for children, pp. 8 and 43–44; WHO, Inheriting a sustainable world? Atlas on children’s health and the environment (Geneva, 2017), p. 49. WHO, “Don’t pollute my future!”, pp. 3 and 13. Ibid., p. 5. WHO, Inheriting a sustainable world?, p. 25. WHO, Preventing disease through healthy environments: A global assessment of the burden of disease from environmental risks (Geneva, 2016), p. 22; WHO, Inheriting a sustainable world?, p. 26. WHO, “Don’t pollute my future!”, p. 6; WHO, Inheriting a sustainable world?, pp. 10–11. UNICEF, “Sustainable development starts and ends with safe, healthy and well-educated children” (May 2013), p. 8. WHO, Inheriting a sustainable world?, p. 25.