Many types of air pollution in the Mexican capital, including many that cause cancer, cannot be monitored due to the lack of financial support from the government, which ''appears to be uninterested in research,'' complain scientists. ''There are many carcinogens in the city's air, such as benzene, mercury and others, whose levels, origin and health impacts are not known because there is no money to pay for studies,'' Violeta Múgica, a scientist working with the Metropolitan Autonomous University, told Tierramérica.

In the Mexican capital — also an air pollution capital of the world — there are state funds for monitoring contaminants like ozone at ground level, nitrogen oxide, lead and suspended particulate. ''There is follow-up for the principal substances, but many other contaminants are excluded,'' said Múgica.

In Mexico, less than 0.5 percent of the gross domestic product is spent on scientific research in general.