Zaynab Begum, her husband and three children live in a tiny bamboo and corrugated hut in a Dhaka slum.
Their living space is smaller than six square metres.
They have no electricity, running water or toilet, and an open sewer runs outside the hut.
“It's difficult to live here because it's cramped and uncomfortable,” she said.
“But my husband is a rickshaw-puller. We can’t afford anything else.”
Zaynab Begum's family are among millions of Bangladeshis who have migrated to the cities in search of work.
Fifty years ago, only about four per cent of the population lived in urban areas, now more than 25% are city dwellers.
Overcrowding and malnutrition are worst among the urban poor, but the urban population is likely to continue to increase as people without land or jobs are driven into cities.
Bangladesh is the world's ninth most populous country, with about 123m people according to official estimates.
The Ministry of Health and Family Welfare says the population is expected to grow to about 210 million by the year 2020.
Despite the relative success of family planning programmes which have brought the population growth rate to between 1.6% and 1.8% a year, already overcrowded Bangladesh will inevitably suffer further strain on its limited resources and land.
The population is expected to stabilise at about a quarter of a billion by 2050, if family planning programmes continue to reduce the birth rate.
But Bangladesh is already one of the world's most densely-populated countries, and its low per capita income is unlikely to increase.
“In a small country like Bangladesh, it will be a really big problem to accommodate such a huge population,” said Mizanur Rahman of the Family Planning Association of Bangladesh.
“Population has been earmarked since 1996 as the number one problem of the country. Social development will be extremely difficult unless we can bring down the population growth rate, and I don’t know exactly how we are going to face this situation. It's a really bleak scenario.”
Experts say it would be difficult to do more to lower population growth in Bangladesh.
“If you look at family planning in isolation, it's been successful,” said Anthea Mulakala of the Bangladesh Population and Health Consortium.
“If you look at the rate at which people have accepted contraceptives, have become knowledgeable about them and have begun to use them, you can see a positive acceptance and a decline in the fertility rate and a decline in the average size of the family,” she said.
“But about 45 per cent of the population are under the age of 15. As these people come into the age of fertility, there's going to be another population explosion here.
“And how the country is going to deal with that, even if they are only having one or two children each because of the success of the family programme, that's going to be a really large problem.”
Food shortages are likely to worsen as the population grows. Joan Fleuren of the World Food Programme said Bangladesh already has a food deficit equivalent to about two million tonnes of grain a year.
“By the year 2020, Bangladesh would have to double its agricultural production,” Mr Fleuren said. “It would be difficult to extend the land area producing grain, so it would have to consider other ways of increasing production such as more irrigation.”
Malnutrition levels are already high. At least half of Bangladesh's people live below the poverty line. They eat only about half of the amount of food that would be considered normal elsewhere in the world.
“Even if agricultural production were to keep pace with demand, there are still going to be a lot of hungry people because they can’t afford food,” Mr Fleuren said.
“Development is the key to feeding a much larger population, and the need for food aid is increasing.”
Bangladesh is already unable to provide jobs, housing and food for all its people, and some analysts fear that there may be an increase in crime and violence as increasing numbers of people have to compete for resources.
“To deal with the population, you’ve got deal with infrastructure and education and many other issues,” Ms Mulakala said. “That is going to be the challenge in the new millennium.”