In 1970, 15% of Indonesians lived in cities compared to over 30% today, and this increases pressure on the urban environment. Industrial pollution is increasing, particularly in Java, and the increasing affluence of the growing middle class drives a rapid increase in the number of motor vehicles and associated emissions. Garbage and waste water services are being placed under increasing pressure. Reliance on septic systems or effluent disposal in open canals and river systems remains the norm, and is a major polluter of water resources. Very few Indonesians have access to safe drinking water and must boil water before use.