The annals of possible solutions to this city's infamous smog problem are full of strange dreams: big holes drilled through the surrounding mountains to let the pollutants out, perfume additives for car exhaust, gas masks for everyone.
Only now, however, have authorities officially contemplated such an idea. On orders from the mayor, researchers and bureaucrats have embarked on what they say is serious study of a plan to blow the contamination away with giant fans.
After what he described as a preliminary evaluation by a dozen distinguished scientists, Mayor Manuel Camacho Solis announced that the plan "deserves more attention" and assigned five scientific faculties to the task.
In a week that has seen four straight days of air-quality emergencies _ forcing government cars off the streets, schoolchildren indoors and factories to cut their operations _ many of the city's residents seemed to think this a good idea.
But to more than a few analysts of pollution politics, Camacho's announcement reflected a classic mix of bad air and big ambition. A noted scientist, who insisted on anonymity, said government support for the fan scheme indicated a need for research into the effects of pollution exposure on the human brain.
As proposed, the project would entail 100 gargantuan complexes spread strategically around the city. At each installation, six 20-foot upright fans would surround 24 gas burners in a ring some 1,350 feet in diameter.
The fans would suck in ground-level air and blow it, at slight angles, into a whirlwind. The incinerator would then warm the air, blasting it skyward though a wide, two-story chimney atop the fans.
In theory, the hot tornado would rise 50 to 100 yards and perforate the layer of cold air that traps pollutants during the city's frequent thermal inversions.
Smog could then rise through the holes to be dispersed by higher-altitude winds. "A hurricane of controlled energy," the chief proponent of the concept, Heberto Castillo, has called it.
Castillo is by profession a civil engineer, and generally is considered a talented one. But he is far better known as a grandfather of the Mexican left, a former political prisoner and presidential candidate who leads the opposition Democratic Revolutionary Party in the capital. And it is the latter identity, as much as the science involved, that has propelled eyebrows toward the haze.
Camacho, for his part, is more than regent of the world's most populous city. In the unacknowledged shadow fight that passes for Mexico's presidential primary, he is widely considered one of two front-runners to represent the governing Institutional Revolutionary Party, or PRI, in the 1994 elections.
Each pretender has been assigned Herculean labors, and one of Camacho's is smog.
By agreeing to consider Castillo's plan formally, many here said, Camacho stands to make a show of open policy-making and neutralize a major opponent. He might also escape charges of ignoring a simple tool to disperse the sick, brownish cloud that afflicts some 20-million people.