To break up street demonstrations, Chile's police fire what is probably the most potent tear gas in Latin America. Santiago residents swear the city's air is only slightly cleaner on normal days. That's an exaggeration, but scientists agree Santiago is one of the world's smoggiest cities. With thousands of buses belching blue-and-black smoke every day, residents complain about sore throats and burning eyes, and doctors warn the smog could cause thousands of deaths from cancer.
Yet few people expect the situation to improve any time soon.
Scientists and environmental activists say Santiago will remain badly polluted for many of the same reasons that smog will continue to plague other Latin cities: With millions of its citizens going hungry and living in inadequate housing, Chile's military regime gives low priority to environmental problems.
But beyond that, analysts say, President Augusto Pinochet is concerned about taking on the politically powerful bus owners, whose vehicles are held responsible for about half of the air pollution.
With few manufacturing plants here, the dirty air is not produced by industrial concerns, as is most of the smog in Latin America's two other badly polluted metropolises, Mexico City and Sao Paulo. Instead, like Bogot'a, Lima, and Caracas, Santiago's pollution comes from a lack of emission controls on vehicles, a reliance on diesel-powered buses, and a poorly designed roadway system.
Atmospheric and geographic conditions worsen the problem. With Santiago nearly surrounded by mountains, covered by a layer of warm air, and with little rain or wind, smog gets trapped. The result is a brown cloud of pollution permanently hanging over the city - particularly during the Southern Hemisphere winter (May through August). By noon, residents can't see the 8,000-foot snowcapped mountain range that forms the city's eastern border.
The problem has worsened steadily over the past decade. As the city has swelled to 4.8 million inhabitants, the number of cars and buses has jumped from 82,000 in 1966 to 373,000 today.
The air has also become dirtier because General Pinochet has actually relaxed emission control laws as part of his free market economic program.
With smog considered a secondary issue and infrequently reported on, few Chileans are aware of the dangers. Smog is viewed more as a nuisance than a health risk. Still, complaints became so vociferous earlier this year that the governor of metropolitan Santiago, Gen. Julio Jara, finally decided to have police remove flagrantly polluting buses from the streets.
Over the next several weeks, police pulled hundreds of buses off the road and wouldn't let them be driven again until owners had them repaired. But on June 1, without warning, bus owners struck back. They refused to operate their vehicles until 10 that morning.
With buses carrying half of the city's 2.5 million rush hour travelers, the stoppage caused chaos. To get to work, desperate commuters mobbed the city's two subway lines, fought over taxis, hitchhiked, and walked.
``It was the first successful strike in the 14 years of military rule,'' says Rafael Asenjo, an environmental lawyer.
Scientists and environmental activists see a ray of hope. The Inter-American Development Bank is financing the first in-depth study of Santiago's smog levels. In July, five smog monitoring devices were installed in the city, and by 1989 initial results will be available.
But Ricardo Katz, a consultant to the governor's office on smog issues, says it will be five to 10 years before Santiago's air becomes cleaner. ``To improve the situation requires political will. But the government treats smog as only one of the many problems the country faces.''