Source: all Africa
There is nothing glamorous about sanitation. Talking about faecal sludge can be something of a conversation stopper. The initial response to mentioning World Toilet Day is often a smile.

But lack of sanitation is not funny. It is a major cause of death and disease and a serious, if too often ignored, barrier to development. Poor sanitation, for example, contributes to over 500,000 child deaths from diarrhoea every year. Half of all hospital visits in developing countries are a direct result of inadequate or non-existent sanitation.

The impact goes well beyond poor health. A lack of toilets is, for example, a contributor to girls missing school. Their absence also forces women and girls to go out at night with all the risks to their personal safety this brings.
And, of course, this all seriously undermines economic performance and prosperity. The World Bank has estimated that poor sanitation costs India more than U.S.$53 billion a year or over 6 per cent of its GDP. Yet despite the terrible damage that poor sanitation does to well-being and prosperity, it remains one of the world's most neglected challenges.

A key part of Millennium Development Goal 7 was to halve the numbers of people without access to sanitation but this was the MDG with the biggest gap between ambition and achievement. The result is that, in 2015, over 2.4 billion people - 40 per cent of the global population - are still forced to practice open defecation or lack adequate sanitation facilities.

The human waste from another two billion residents in towns and cities is not safely treated and can end up dangerously polluting neighborhoods, rivers, lakes or seas. Additionally, by 2030, water demand is likely to increase by 238% in sub-Saharan Africa, particularly in cities. This is 3 times more than any other region in the world.

Even when toilets are available, many times they must be shared within a large community. On average, one in four urban Africans only has access to a shared toilet.

It was to draw attention to this collective failure and the urgent need to correct it that the UN officially recognised World Toilet Day on November 19, 2013. As the UN Special Rapporteur Catarina de Albuquerque said, lack of sanitation was "a euphemism to describe the undignified life of billions of people who have no place to defecate or urinate and have to do it without conditions of safety, hygiene, privacy or dignity".

But while World Toilet Day helps focus attention on this grim reality, it does not, of course, cover the breadth of the sanitation challenge. The provision of toilets is a necessary first stage but it is by no means the complete answer. Damage to public health can be almost as severe even when everyone is using a toilet if the waste produced is not safely treated. And all too often, this is the case.

The waste - with its disease carrying pathogens - is often piped into ditches, dumped into fields or released into rivers and the sea. Unsurprisingly, the consequences are continuing high rates of illness. So while toilets are an essential part of overcoming the sanitation challenge, they are the means not the end. They will only deliver the results we want if coupled with measures to reduce the amount of untreated waste.

But achieving this aim urgently needs new thinking. It will be impossible, in the fast-growing conurbations of the developing world, to replicate the expensive and resource-heavy sewage infrastructure in London and New York. We have to find ways of achieving the same results in a much more cost-effective and innovative way.

These are the breakthroughs that the Bill and Melinda Gates Foundation is working with partners across the world to identify, develop and roll out. We are focusing first on urban sanitation where dense neighbourhoods can most quickly benefit from innovations in technology and processes, but we expect the same technologies can later be adapted for use in more rural communities.

We are supporting work that includes the development of the next generation of toilets which are cheap to run without the need for sewer or water connections, and low-cost approaches to treating faecal sludge that results in usable products, such as energy or fertilisers. Such uses will also help encourage new public and private providers and partnerships to collect and treat waste.

What we also know is that such investment in sanitation will deliver an immediate return in improved health, a better environment and increased productivity. The World Bank has estimated that every £1 spent on improving sanitation delivers more than £5, on average, in social and economic benefits.

So while sanitation may never be a glamorous subject, without it our wider hopes for development cannot be achieved. It is the key to healthier and more sustainable and resilient cities - and World Toilet Day reminds us that such goals need to be talking about openly, not treated as taboo.