Over the past 12 years, WHO and UNICEF estimate that an additional 1.1 billion people have gained access to an improved source of drinking water - bringing global coverage rates up to 83 per cent, from 77 per cent in 1990.

South Asia shows the greatest gains in drinking water coverage, increasing from 71 per cent to 84 per cent. Great progress has been made in India and China. But Asia still accounts for two-thirds (675 million) of the people worldwide whose drinking water still comes from unsafe sources like rivers, ponds, and vendors.

Sub-Saharan Africa has shown patchier progress. While countries such as Angola, Central African Republic, Chad, Malawi and Tanzania have all increased drinking water coverage by over 50 per cent, the region's overall drinking water coverage has increased by only nine percentage points since 1990 - to 58 per cent - leaving 288 million people still with no choice but to rely on water that could leave them sick or dead.

In addition to the encouraging progress made by individual countries across the globe, much of the new coverage in developing countries has come from water piped directly into homes. Roughly half of the world's population now drinks piped water. WHO and UNICEF stress that substantive economic benefits will result from this increase4: piped water into the home is associated with the greatest improvements in household health, and frees women and girls from the burden of water carrying, giving them greater time for work, family and school.

Progress toward the sanitation goal

While more than 1 billion people have gained access to basic sanitation services, population growth has outstripped our efforts, translating the numerical gains into much smaller gains in proportional terms. In 1990, 49 per cent of world had access to basic sanitation facilities. Today, that figure has increased by only nine percentage points, leaving us way behind schedule for the 2015 MDG target (75 per cent coverage). If this trend continues, the world will miss its sanitation pledge by over 500 million people.

Eastern Asia shows the greatest increase in coverage, from 24 to 45 per cent, fuelled primarily by gains in China. But Asia is still home to three out of the four people worldwide who don't have use of even a simple improved latrine. Over half of all people living without improved sanitation live in India (735 million) and China (725 million).

Sub-Saharan Africa, meanwhile, has the lowest percentage of people with access to basic sanitation facilities - 36 per cent, an increase of just four per cent since 1990. In the developing world as a whole, only 49% of people had access to adequate sanitation facilities, while in the world's developed regions, 98% of people did.

Worldwide, Benin, India, Madagascar and Myanmar made especially rapid progress towards the sanitation target. But only two out of the world's nine developing regions - Eastern Asia and South-eastern Asia - are on track to meet the sanitation goal, with north Africa and Latin America very close behind.

3Improved drinking water sources include: household connection, public standpipe, borehole, protected dug well, protected spring, rainwater collection.

4"Evaluation of the Costs and Benefits of Water and Sanitation Improvements at the Global Level", commissioned from the Swiss Tropical Institue by WHO in 2004, estimated that, for every US$1 invested in water and sanitation improvements, the economic benefit would be between US$3 to US$34 - depending on the type of water system and region in which the investment occurs.

World facing "silent emergency" as billions struggle without clean water or basic sanitation, say WHO and UNICEF: 1,2