An ambitious plan to build five million affordable homes within five years in Pakistan will tap student architects and use local materials and new technologies to keep costs low, a senior government official said on Thursday.Prime Minister Imran Khan has committed to build four million homes in rural and urban areas and one million homes in peri-urban areas over the next five years.It is the biggest government-backed housing programme ever attempted, and will meet half of Pakistan's needs, said Zaigham Rizvi, chairman of the federal task force on housing."Affordable housing is not just an issue in poor countries; it is an issue in nearly every country," Rizvi said on the sidelines of a housing forum in Bangkok."But the promise of 'housing for all' is usually nothing more than a political slogan, and rarely implemented because of a lack of will or because the institutional framework is lacking," he said.By 2030, more than half of Pakistan's projected 250 million citizens are expected to live in cities, compared to 36 per cent now, according to the United Nations.About a quarter of the country's population currently lives below the poverty line, according to the Asian Development Bank.Authorities in Pakistan are developing more than two dozen pilot villages in Punjab, the nation's most populous province, using common lands - wasteland or grazing land - and unused public lands, Rizvi said.The homes are designed by student architects who will use technology and local materials to keep costs low, while taking into account cultural and geographical needs."We want to engage the youth in solving the nation's problems. In the village, they are not used to high-rise buildings, so they will be at most one-storey buildings," he said."Similarly, most homes keep cattle, so there will be a common area to keep them," said Rizvi, a former consultant to the World Bank and the UN's housing agency, UN-HABITAT.It is hoped the pilot projects will be scaled up once deemed a success, he said, adding that several local and foreign firms are keen to build the low-cost homes.The government will tailor financing schemes for people who want to become homeowners but may not have bank accounts or have only a seasonal income, he added.Globally, about 1.6 billion people live in inadequate housing, with most living in slums and informal settlements in cities, according to UN estimates.In India, Prime Minister Narendra Modi has pledged to provide "Housing for All" by 2022, with a goal of building 20 million urban housing units, backed by subsidised loans and incentives for developers.The rapid growth of cities in Pakistan is expected to accelerate the conversion of farmland into built-up land. Earlier this year, Prime Minister Khan banned the use of farmland for new housing, in a bid to stop cities encroaching on agricultural areas.Housing had traditionally not been a part of urban planning, which had led to a piecemeal approach, said Rizvi."With increasing urbanisation and migration, housing has to be a critical part of urban planning. Otherwise, we risk neglecting the needs of millions of vulnerable people," he said.