Environmental issues in Indonesia are associated with the country's high population density and rapid industrialisation, and they are often given a lower priority due to high poverty levels, and an under-resourced governance. Most large palm oil plantations in Indonesia owned by Singaporean rich conglomerates who employ thousands of local natives Indonesian. Issues include large-scale deforestation (much of it illegal) and related wildfires causing heavy smog over parts of western Indonesia, Malaysia and Singapore; over-exploitation of marine resources; and environmental problems associated with rapid urbanisation and economic development, including air pollution, traffic congestion, garbage management, and reliable water and waste water services. Deforestation and the destruction of peatlands make Indonesia the world's third largest emitter of greenhouse gases. Habitat destruction threatens the survival of indigenous and endemic species, including 140 species of mammals identified by the World Conservation Union (IUCN) as threatened, and 15 identified as critically endangered, including the Sumatran orangutan. History and background For centuries, the geographical resources of the Indonesian archipelago have been exploited in ways that fall into consistent social and historical patterns. One cultural pattern consists of the formerly Indianized, rice-growing peasants in the valleys and plains of Sumatra, Java, and Bali; another cultural complex is composed of the largely Islamic coastal commercial sector; a third, more marginal sector consists of the upland forest farming communities which exist by means of subsistence swidden agriculture. To some degree, these patterns can be linked to the geographical resources themselves, with abundant shoreline, generally calm seas, and steady winds favouring the use of sailing vessels, and fertile valleys and plains—at least in the Greater Sunda Islands—permitting irrigated rice farming. The heavily forested, mountainous interior hinders overland communication by road or river, but fosters slash-and-burn agriculture. Each of these patterns of ecological and economic adaptation experienced tremendous pressures during the 1970s and 1980s, with rising population density, soil erosion, river-bed siltation, and water pollution from agricultural pesticides and off-shore oil drilling. Marine pollution In the coastal commercial sector, for instance, the livelihood of fishing people and those engaged in allied activities—roughly 5.6 million people—began to be imperiled in the late 1970s by declining fish stocks brought about by the contamination of coastal waters. Fishermen in northern Java experienced marked declines in certain kinds of fish catches and by the mid-1980s saw the worst virtual disappearance of the fish in some areas. Effluent from fertiliser plants in Gresik in northern Java