Clean water is highly essential since it is used in every part of daily life. Supply, maintenance, and management of water resources help economic development and poverty reduction. In 2010, the UN General Assembly acknowledged that safe, clean drinking water and sanitation were integral to the realization of all human rights. However, until now, 2 billion people are drinking polluted water. Polluted water can cause diarrhea, cholera, dysentery, typhoid, and polio. More than 500 thousand people are dead by diarrhea resulted from dirty water every year.

Safe and easily accessible water is essential in socioeconomic aspects. If you have clean water near your house, and no need to draw water from well far away, then you can spend the time on education and economic production. You don’t have to take a round about, harsh way, and can escape from the danger of diseases resulted from wasted water. The vulnerable, children can go to school healthily and live a better life with education in the long run. 

Clean, sanitary facilities are vital, too. It can prevent diffusion of parasite and tropical diseases, balanced nutrition, and primarily provide gender-separated toilets to raise attendance rate of school for girls. 2 billion people don’t have sanitized toilet over the world. No less than 10% of people of them eat food from earth polluted by wasted water. These environments cause cholera, diarrhea, hepatitis A, typhoid, and polio. With a little improvement, sanitation shows inequalities depending on regions, countries, even within states. For example, in South Asia, people equipped with sanitation facilities increased from 22% in 1990 to 47% in 2015, showing improvement, while Sub-Saharan Africa, from24% in 1990 to 30% in 2015, prominently falling behind.

UN Sustainable Development Goals 6 'Ensure availability and sustainable management of water and sanitation of all' includesachieving universal and equitable sanitation and hygiene for all by 2030 in Target 6.1 and 6.2. International society is making its efforts in various ways for it.

Recent researches show that environmental pollution and climate changes can cause serious health problems. 97% of climatologists suggested that climate change has been created by human activities such as using fossil fuels and destroying tropical forests. By 2050, New York would have days over 32-degree temperatures three times more days than now. The economic effect would be huge. There is an increasing possibility of respiratory diseases such as asthma, endemic diseases, food depletion caused by plant decrease and infection, furthermore, Post-Traumatic Stress Disorder, and depression.

The effect of climate change appears higher in developing countries than developed countries, because related facilities or policies are not equipped soundly. In particular, poor people and children near the equator area are already affected by climate-related diseases(malnutrition, diarrhea, or malaria) prevalent, which means that they are more vulnerable to climate change. International society should plan cost-efficient strategies in related sectors. Besides, we should keep our health by efforts to lessen climate change, such as using renewable energy.

Nutritional imbalance may seriously threaten one’s health. Global society now has extreme ends, malnutrition, and obesity. 

As of 2014, four hundred sixty-two million people are underweight; meanwhile, 1.9 billion adults are overweight or obese. Starvation and malnutrition intervene physical growth of children's body and brain and cause pregnant mothers, fetuses, and newborns to die. The rate of obesity and overweight is internationally increasing. Therefore chronical diseases such as cancer, cardiac ailments, and diabetes are threatening people’s life.

According to WHO data in 2016, 41 million infants under-5-year-old children are overweight or obese, while 154 million had suffered undergrowth due to chronic malnutrition. About 45% died from malnutrition, and this occurs mainly in low-income countries and middle-income countries.

Micronutrient (e.g., vitamin A, iodine, and Iron) deficiency is a crucial nutrition problem. Iodine deficiency is one of the common reasons of children failing cognitive ability growth, and it may also threaten mental health, even life. Iodine deficiency during pregnancy cause stillbirth or spontaneous abortion. Vitamin A, as well, is one of the severe health issues, causing blindness or taking a life of children if not provided enough. It frequently happens in developing countries in Africa or southeastern Asia.

International society is finding numerous ways to solve these problems. Improving nutrition is included in UN Sustainable Development Goals 2 ‘Zero Hunger’ and Goal 3
‘Ensure healthy lives and promote well-being for all at all ages.’  Recently, Nutrition International, UNICEF, and WFP jointly has researched iodized salt with financial support from Canada. Iodized salt introduced to countries in which iodine deficiency has been grave was hugely successful.