UNITED NATIONS, March 22 (Xinhua) -- UN Secretary-General Antonio Guterres on Thursday warned that increasing demand for freshwater and growing impact of climate change are making water scarcity an enormous concern.

Demand for freshwater is projected to grow by more than 40 percent by the middle of the century, and climate change, which is picking up pace, is adding to the pressure, he said in a speech at the launch of the International Decade for Action on Water at the UN General Assembly.

The launch of the action plan coincides with World Water Day, which falls on March 22.

Guterres said 40 percent of the world's people are now affected by water scarcity; 80 percent of waste water is discharged untreated into the environment, and more than 90 percent of disasters are water-related.

More than two billion people lack access to safe water, and more than 4.5 billion people lack adequate sanitation services, he said.

Many of the most serious diseases in the developing world are directly related to unsafe drinking water, poor sanitation, and insufficient hygiene practices.

The United Nations stands ready to help countries to promote policy dialogue, exchange best practices, raise awareness and forge partnerships, he said.

"The growing water crisis should be much higher on the world's radar. Let us work collectively toward a more sustainable world, and an action-packed decade of water for sustainable development," he said.

The action plan on water seeks to transform the approach to water supply, sanitation, water management and disaster risk reduction in order to better tackle water stress, combat climate change and enhance resilience; to align existing water and sanitation programs and projects with the 2030 Agenda for sustainable development.