In a message for World Water Day, Pope Francis stressed the need to remember the suffering of billions of people who do not have reliable access to clean water in their homes.

"Joint work is essential to eradicate this evil [of a lack of access to clean water] that afflicts so many of our brothers and sisters," the pope said.

"It will be possible if we join efforts in the search for the common good, when the other has a real face, takes center stage and is placed at the center of debate and initiatives. This is when the measures adopted will take on the flavor of encounter, and the value of responding to an injustice that needs to be healed."

Pope Francis sent a message to Professor José Graziano da Silva, director general of the United Nations' Food and Agriculture Organization on March 22, World Water Day.

Observed annually by the United Nations to highlight the need for access to safe water, the theme of this year's World Water Day is "Leaving no one behind."

One of the UN's Sustainable Development Goals set in 2015 is ensuring clean water and sanitation for all people by 2030. Currently, up to 2.1 billion people lack safe water at home, according to the United Nations. Nearly two-thirds of the global population struggles to find water during at least part of the year.

In his message, Pope Francis noted that water is crucial "for the balance of ecosystems and human survival, and it is necessary to manage it and take care of it so that it is not contaminated or lost."

All people are called "to value and defend this good," the pope said.

He emphasized the need for education, in order to create an awareness of the suffering caused by those who lack clean water or experience other environmental challenges.

"This task of raising awareness is a priority in a world in which everything is discarded and disdained, and which in many cases does not appreciate the importance of the resources we have at our disposal," he said.

With environmental challenges growing, Pope Francis said, "the disadvantaged of the earth challenge us to find a remedy for the lack of water in their countries; they also challenge us, from their poverty and limits, to accord the just value to this good, essential for the development of all peoples."

He called for financing plans, long-range water projects, and a new vision of water that is seen as a good for humanity, not just a commodity governed by laws of the market.

The pope voiced prayers that World Water Day may contribute to the good of people currently suffering from a lack of clean water.

"Access to this good is a fundamental human right, which must be respected, because the life of the people and their dignity are at stake," he said.