One in four health centers in the world lacks water services, putting around 1.8 billion people at increasing risk of contracting COVID-19, the World Health Organization (WHO) said here on Monday.

This result was concluded from a study based on 165 countries' data, which was jointly reported by WHO and the UN children's fund (UNICEF).

"Working in a healthcare facility without water, sanitation and hygiene is akin to sending nurses and doctors to work without personal protective equipment," said WHO Director-General Tedros Adhanom Ghebreyesus.

The situation is particularly bad in least developed countries, he added.