It's a daily ritual for eight-year-old Bismillah. Every morning, five grimy plastic cans slung over his tiny shoulder, he descends a rugged hillside, negotiating the steep pitches of rubble and gravel with goat-like agility. At the bottom of the hill, he waits under the broiling sun in a long queue leading up to a spigot. But wait he must or his family will be left without drinking water for the day. Bismillah lives with his handicapped father, mother and four sisters in a mud-and-wood house in a cramped settlement clinging to a shale-brown hill overlooking Kabul. With no direct water supply, dwellers of these rudimentary housing settlements - all illegally built - must lug their water from the bottom of the hill. 'Life is hard,' says Suraiya Begum, Bismillah's mother, her face hidden behind the lavender fabric of her burqa. 'We wouldn't live here if we had a better choice.' Six years after the US-led invasion, ask ordinary Afghans about the biggest challenge they face, and their answer isn't likely to be the Taleban. It is, in fact, to find a roof over their heads. Kabul is in particular need, because of the destruction of nearly 70,000 houses in almost 30 years of war. And a steady inflow of returnees has further exacerbated the problem. With a population of 800,000 before the invasion in 2001, Kabul is now home to more than 4 million, many of them refugees who have returned home since the fall of the Taleban. It is estimated that as much as half of Kabul's population lives in squatter settlements. The city is sinking under the weight of its own residents. Kabul's most urgent urban planning issues are linked to its rapid population growth. The situation is the same in other larger cities as well - like Jalalabad, Mazar-i-Sharif and Kandahar. According to UN estimates, from 2000 to 2015 the national population is expected to increase by 14 million to a total of about 37 million; more than half of this growth will be in urban areas. So far, foreign firms have invested US$4.5 billion in rebuilding Afghanistan, but very little of it has gone into housing construction, according to Omar Zakhilwal, the director of the Afghanistan Investment Support Agency in Kabul. In fact, an acute shortage of affordable housing is forcing people to recklessly build mud houses on the slippery slopes of denuded hills around Kabul. And overcrowding has put a lot of pressure on the already frail civic infrastructure of the city. The UN says Afghanistan is the world's sixth least developed country. Only 13 per cent of Afghans have access to safe water, 12 per cent to adequate sanitation and just 6 per cent to electricity. Life expectancy is 44 years, compared with 59 years for low-income countries worldwide. For Suraiya Begum's family, life in this overcrowded settlement is unforgiving. When it rains, her porous roof leaks and a flood of muddy excrement flows down the slopes, filling up sewers and cesspits already choked with garbage. Mounds of trash collect in heaps in the alleyways leading up to her house. The open sewers are besieged by flies and disease. Sanitation facilities are scarce. There is a dearth of potable water; piped city water reaches only 18 per cent of people in Kabul. Daily power cuts last from dawn until dusk in the winter - longer in the summer. Afghanistan's Ministry of Urban Development, with World Bank assistance, is now in the process of upgrading formal and informal settlements in Kabul. This US$28.2 million project, which will take at least a few years to implement, will improve infrastructure and provide basic services like drinking water, sanitation, surface water drainage, concrete roads and street lighting. 'Given a vast majority live in these settlements, the solution is to upgrade, not demolish these homes and make more people homeless,' says Yousaf Pashtun, the urban development minister, who is an architect and town planner by training. But despite the government's efforts, Kabul is facing a chronic shortage of housing for the poor. The per capita income in this post-Taleban nation, according to the World Bank, increased from US$180 in 2002 to US$300 in 2006. The figure is expected to reach US$500 soon. Still, buying a house or an apartment remains a distant dream for most of Kabul's residents. A two-bedroom apartment in Kabul can cost US$200 to US$400 a month, compared to US$7 for a three-bedroom home in 1978. In the neighbourhoods of Wazir Akbar Khan and Shar-e Now, private housing rents have reached US$7,000 a month. That makes it impossible for the poor to pay for housing in Kabul, and dramatically widens the class of impoverished Afghans. Last year, the Agency Co-ordinating Body for Afghan Relief expressed concern that Afghanistan's housing prices were spiralling out of control and making a difficult situation worse for the Afghan poor. 'I didn't think we would face so many problems when we came back to Kabul,' says Sangar Khan, a 24-year-old Afghan who returned to the country from Pakistan, where he had fled during the Taleban's reign. 'We keep hearing so much money is being given to the reconstruction of Afghanistan, but getting a [home] is the biggest challenge. Renting a house is just not affordable any more.' Mr Khan lives in a squatter shack in another informal settlement that isn't rent-free. As most land in Kabul is claimed by one or more owners - individuals, companies or government institutions - squatter households are usually obliged to pay some amount to remain on a property. Mr Pashtun says he is aware of the acute housing shortage. The Afghan government, he says, with an investment of more than US$200 million, is in the process of building a small satellite town in northeast Kabul called Shar-i-Sabz, with 100,000 units of housing due to be completed in the next three years. But beyond the efforts of the government, Mr Pashtun says, the private sector can play a big role in building housing for war-weary Afghans.