Approximately 68% of the population lives in rural areas and the majority are farmers with incomes reliant upon subsistence agriculture. Rapid change has had a disruptive effect on social structures. Urban migration to Bangkok, the capital city, has led to serious problems of congestion, land shortage, and water and air pollution. Although a period of fast economic and social transformation has improved the quality of life, there is now evidence that the income inequalities both within and between regions and between rich and poor groups are widening. The replacement of the extended family by the nuclear family has weakened the sense of community and traditional forms of co- operation and safety nets, increasing the vulnerability of disadvantaged groups. Drug addiction and crime are on the increase.