Mexico City, known the world ’round for its air pollution, will soon unveil a new 10-year plan to tackle the problem. The plan by the Metropolitan Environmental Commission will aim to reduce ozone and particulate levels in the air by taking such steps as retiring old trucks, limiting cargo circulation hours, using more natural gas in public transportation, and giving taxi drivers incentives to buy new cars. The city’s environment secretary, Claudia Sheinbaum, said the government would also issue more pollution emergency alerts, which ban high-emissions cars from the road. Even though pollution levels in Mexico City have improved in recent years, Sheinbaum said that the city continued to exceed international standards for ozone nine out of 10 days.