MercoPress. South Atlantic News Agency

First pre-emergency pollution alert for 2003 in Santiago.

The Chilean government on Sunday announced the year's first pre-emergency environmental alert with the aim of protecting the health of the capital's six million residents, due to the high level of pollutants detected in the atmosphere.

During the Southern Hemisphere's autumn and winter - particularly between the months of May and August - the lack of breezes over Santiago and the city's topography are such that toxic gases collect and become concentrated there.

The pre-emergency measure is the first one announced by the city council so far in 2003, and it forbids the use on Monday of 250,000 vehicles and bars 1,019 industrial locations from opening their doors for business.

On Sunday, some neighbourhoods in the western portion of the city registered atmospheric pollution levels above 200 micrograms per cubic centimetre of air, the level considered dangerous by the World Health Organization (WHO).

The pre-emergency alert will put some 60 percent of the non-catalytic-engine vehicles out of service for the day, and will close 30 percent of the industries or "fixed sources" of smoke, chemicals and other atmospheric pollutants.

In addition, the heating systems of some hospitals and other buildings - including banks, hotels and some public institutions - in the city will be shut down.

Also, physical education classes and sporting events for students in the capital will be suspended to guard the public against health damage from inhaled pollutants.

City authorities did not rule out extending the alert for several days, given the atmospheric conditions prevailing in the capital.

In 1998, Santiago was listed as the eighth-most-polluted national capital in the world by the WHO.

Some 800,000 vehicles are used daily in the capital. Also, it is surrounded by an industrial zone, the factories in which send huge amounts of toxic chemicals into the atmosphere.

To top things off, the city is surrounded by mountains which block breezes at certain times of the year.