^In 1997, a drought associated with a severe ENSO (El Nino-Southern Oscillation) event was the cause of significant disruptions to village food and water supplies in PNG, as well as the failure of the water supply to towns and smaller service centres, mine closures and disruption to the supply of electricity. There were severe shortages of food and water, with garden produce declining by 80 per cent. Up to 40 per cent of the rural population (1.2 million people) were without locally available food by the end of 1997. The health of rural people declined and in many isolated places the mortality rate increased. Many thousands of people migrated to towns and cities to live with wage-earning relatives. A traditional social support system (known as the wantok system) saw town dwelling people buying imported food for rural dwelling relatives in distress.