Globally, an estimated 2,000 children under the age of five die every day from diarrhoeal diseases and of these some 1,800 deaths are linked to water, sanitation and hygiene, according to the report.
The United Nations Children's Fund (UNICEF) child mortality data reveals that about half of under-five deaths occur in only five countries: India, Nigeria, Democratic Republic of the Congo (DRC), Pakistan and China.
Of the 783 million people worldwide without improved drinking water, there are 119 million in China; 97 million in India; 66 million in Nigeria; 36 million in DRC; and 15 million in Pakistan.
The figures for sanitation are even bleaker. Those without improved sanitation in these countries are: India 814 million; China 477 million; Nigeria 109 million; Pakistan 91 million; and DRC 50 million.
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Despite a burgeoning global population, these deaths have come down significantly over the last decade, from 1.2 million per year in 2000 to about 760,000 a year in 2011. However, UNICEF said that is still too many.
"Sometimes we focus so much on the big numbers, that we fail to see the human tragedies that underlie each statistic," said Sanjay Wijesekera, global head of UNICEF's water, sanitation and hygiene programme.
"If 90 school buses filled with kindergartners were to crash every day, with no survivors, the world would take notice. But this is precisely what happens every single day because of poor water, sanitation and hygiene," Wijesekera said in a statement.
Wijesekera said the progress already made since 1990 shows that with the political will, with investment, with a focus on equity and on reaching the hardest to reach, every child should be able to get access to improved drinking water and sanitation, perhaps within a generation.