MEXICO CITY — Mexico has launched an ambitious plan to drastically cut fuel emissions and improve air quality, the environment secretary said Tuesday.

Jose Luis Luege Tamargo told a news conference his department has signed an agreement with the environment and finance departments to reduce sulfur emissions by 50 percent before 2020.

The restrictions on sulfur emissions and small particles will go into effect in July and will be gradually expanded each year until 2009, Luege said. He said that the limits are among "the strictest in the world."

Mexico City is among the world's most polluted cities. The metropolis of 18 million failed to meet acceptable air quality standards for ozone limits 284 days last year, Luege said, though earlier environmental measures have led to major improvements in other pollutants, such as lead.

Cars and trucks, especially those that run on diesel fuel, are the biggest polluters. An estimated 6 million cars clog the capital's streets each day, and that number is expected to double in 15 years, Luege said.

According to a study by Mexico's 1995 Nobel chemistry prize winner, Mario Molina, who is coordinating a 10-year project to improve air quality in Mexico City, the city's residents lose 2.5 million working days every year due to health problems caused by particle matter, such as soot.

Luege said Mexico's government-owned oil company, Petroleos Mexicanos, will have to reduce the sulfur content of its diesel and unleaded gasoline by more than 84 percent by 2008.

Source: Associated Press