Sanitation facilities seldom appear on the list of priorities drawn up by a poor Third World family. A latrine seems no great advance. It just confines smells and flies to a small but rather than distributing them far from home.
No-one talks about it - but everyone has their own taboo-bound methods of dealing with this most basic of bodily functions. Nowhere is this truer than on the Indian subcontinent. Here, from time immemorial, the problem has been dealt with by assigning it to people of the rock bottom social layer. And their task in life - the removal and disposal of 'nightsoil' - has classified them lower than even the lowest caste; beyond the caste system altogether, as `untouchable'.
So it is against all the odds that in certain corners of Karachi's slums a soak-pit latrine has proved to be the springboard for community development.
Karachi is Pakistan's main port and the financial and industrial hub of the country. One-third of the city's six million people lives in the slums - the katachi abadis (Literally `temporary dwellings'). And one in four children born in these slums die before the age of five: victims of the usual poverty duo - poor sanitation and low health awareness.
In the spring of 1979 the Dutch Advisory Mission (DAM) proposed a technical cure for Karachi's sickness: a soak-pit connected to a squat latrine by a four-inch pipe with a water seal, the whole installation costing 1,200 rupees (about $120).
Cheap, simple, effective: it seemed the perfect solution. But the municipal corporation of Karachi (the KMC) were not interested - despite the handsome subsidies offered by the Dutch government. The KMC prefers to supply water and sewerage systems on a mass scale, and at a rate, given the water shortage, that would get around to the 150,000 people of the Baldia slum township in about 1992. A discouraged DAM gave up and went home.
But the soak-pit project was not forgotten completely. It finally got off the ground - or rather, under it - in August 1979 when UNICEF managed to interest two organisations - the local branch of Jaycees International and the Social Studies Department of Karachi University - in it. UNICEF was to provide materials - sand, cement, squatting plate, pipes - and Jaycees and the University were to build the latrines and try to get the slum-dwellers interested in the scheme.
From the start Jaycees and the University adopted different approaches. Jaycees volunteers did everything - digging, building, assembling materials. All the residents were required to do was `accept' the completed latrine. The University students went about it in a different way. Ms Quratul Ain, the project's community organiser, insisted that only families who both asked for a latrine and were willing to help build it would be included in the scheme. Because only the keenest households were provided with latrine-building materials, and because they had helped construct it themselves, these families made sure they used it properly. In fact there was such a marked difference in the rates of success of the two approaches that the construction - only one has now been dropped: no-one gets a free soak-pit any more.
Turk Colony, a katchi abadi in Baldia township established almost 35 years ago at the time of Partition, is a rabbit warren of narrow lanes, cubby-hole shops and rickety houses. Most Turk Colony dwellers used to use a bucket latrine emptied at dawn by the 'untouchable' sweeper and his cart. Today the sweeper no longer bothers to call on Turk Colony residents. Nearly every diminutive courtyard now boasts a new soak pit latrine.
In Turk Colony the organisation of every stage of latrine construction - bar paying for materials - has been taken over by the local people. A key figure is the local mason, Karim Daya, now President of the newly-formed Turk Colony Welfare Society.
The Turk Colony Welfare Society selects the order in which households will have their latrines installed and puts pressure on reluctant households. Why should they put up with a dirty courtyard in the midst of their clean ones just because one family is unwilling to dig a hole? And for those who can't dig holes themselves, there are other solutions.
Miriam Jamal's husband is mentally handicapped and unable to provide for them. There was no-one in her family to dig the pit and she could not afford the 300 rupees ($30) to pay for someone else to do it. So Mrs. Hawa Bai, a better-off neighbour, paid for the digging. In the corner of Miriam Jamal's tiny yard there is now the slatted door of her new latrine.
But the Turk Colony Welfare Society didn't stop at latrines. It has raised enough money from its 77 members to buy 900 rupees-worth ($90) of tools which it now loans out. It has organised lane-cleaning and is beginning a campaign to bring street lighting and drainage to the area. Karim Daya has gone into the brick-making business to cut down latrine construction costs. And the society has meeting rooms rented for a nominal fee from a local spiritual leader. Now, having formed a women's club for health education and sewing classes, their sights are set still higher - they want a maternity clinic in Turk Colony.
And all this from the humblest of humble beginnings - the simple, taboo-bound pit latrine.
There have been problems. Some latrines don't soak away properly because the soil is too rocky, or too densely packed. Some were dug too shallow and filled in after 18 months. Only a few hundred of the thousands planned for Baldia township have yet been built. But in Turk Colony and those other katchi abadis where it has caught on it has proved that even the most unlikely thing can spark off the process of community development - if it's what people want and if they can run the project themselves.
Maggie Black is a development journalist; currently editor of UNICEF News. The views expressed here are her own and do not necessarily reflect those of UNICEF.