Some of the factors that define the challenges to access water :
Less than 1 percent of all water on Earth is available as groundwater and surface water suitable for humans to use for drinking and cooking. That 1% is not distributed across the globe in proportion to the human population. For example – India has just 4% of the world’s fresh water but 16% of the global population.
Precipitation, which replenishes groundwater and surface water resources, does not fall evenly over the face of the Earth. Additionally, some times of the year are rainy, other times dry. Water resources can be abundant at some times and in some places, but extremely sparse in others.
For more than a billion people in developing countries, water is scarce and frequently contaminated, posing a health risk. In these parts of the world, contaminated drinking water along with primitive (or nonexistent) sanitation systems annually result in widespread illness and millions of deaths. Also note: The majority of the water-borne disease victims are children.