Three separate environmental problems, each serious in its own right, have combined to create an air-quality disaster on a huge scale. Suddenly, pollution has transformed itself from an irritating side-effect of rapid economic growth to a threat to an entire region's economy and public health.
The initial cause of the smog was the uncontrolled burning of brushwood and forests in parts of Indonesia and Malaysia, started by small farmers and plantation owners wanting to clear land.
These fires, along with accidental blazes, went out of control because of a continuing drought linked to the phenomenon of El Nino, a major fluctuation in the workings of the planet's climate which takes place roughly every five years. The latest El Nino, which began six months ago, is particularly severe and may turn out to be the most destructive this century. Some climate scientists say that man-made global warming, caused by the burning of fossil fuels, is making the fluctuations more severe.
The third factor is the high levels of pollution in many of the region's towns and cities caused by fast-growing road traffic, fossil fuel power stations and industry operating with few pollution controls.
A senior Indonesian official admitted yesterday that two people had already died, and that more than 32,000 were afflicted with respiratory illnesses caused by the smog. Many more deaths are anticipated.
In Kuching, in the Malaysian province of Sarawak, schools, offices, factories and the international airport have been closed and a state of emergency has been declared after daytime visibility was reduced to a few yards. An Air Pollutant Index (API) of between 100 and 200 is considered "unhealthy", while anything between 300 and 500 is "hazardous". In Kuching, it was 651 yesterday, down from a record 839 on Tuesday.
In Sarawak, about 5,000 people are reported to be turning up at local hospitals every day, complaining of respiratory problems, and there has been panic buying of food and water supplies in anticipation of a possible evacuation.
In the Malaysian capital of Kuala Lumpur, 75 US embassy staff and their families have been allowed to leave if they feel ill-effects from the smog. Those who remain will be rotated in and out of the country "to minimise any possible health effects".
The smog already covers most of Malaysia, Brunei, and Singapore, as well as parts of Papua New Guinea. Recently, south-western winds have driven it as far as the Philippines; on the southern island of Palawan, fishermen have been confined to harbour by the reduced visibility.
The smoke is hampering efforts to bring relief to victims of a severe drought and food shortage affecting tribal people of New Guinea. Missionary planes carrying relief supplies have been unable to land in parts of the remote Indonesian province of Irian Jaya, where some 250 people have already died of starvation and cholera.
Monsoon rains are desperately needed, to douse the flames and wash out the smog. The use of cloud-seeding planes to create rain has made a small difference over Kuala Lumpur, and the Malaysian government says it is now studying plans to spray water from the top of tall buildings to dissolve some of the pollutants.
The region's leaders have plenty else to preoccupy them, including a financial crisis which has caused their currencies and the stock exchange to plummet in value.
Malaysia's Deputy Prime Minister, Anwar Ibrahim, attending the World Bank and International Monetary Fund meeting in Hong Kong, said foreign fund managers had expressed worries about the smog affecting the already unstable financial markets.
Hundreds of cities and towns in developing countries now suffer pollution levels which are as bad or worse than the lethal "pea-souper" smogs that London and other big Western cities suffered before the 1960s. Millions of lives are shortened by heart and lung disease as a result.
While some developing countries, such as Mexico, have begun strenuous efforts to curb their pollution problems, the disaster in South-east Asia shows that air quality is now a cross-border problem.
Countries in South-east Asia will have to co-operate and sign treaties to cut the overall burden of pollution and clean the air, as has been done in North America and Europe. Even Singapore, with relatively low pollution levels of its own and an income level higher than that of the UK, has been unable to escape the fall-out.Reuse content