Crying out loud
Mexico City is one of the most polluted cities in the world. But air pollution levels in Delhi are several notches higher than Mexico City and steadily rising. The main reason being that while administration in Delhi fails to address the problem, Mexican authorities are making serious efforts to improve the situation. And the results are already showing. In May 1998, Mexico City authorities decided to impose a pollution emergency during days when the particulate matter level in the air is considered detrimental to public health.
In Mexico City, a Phase 1 emergency is declared when pm 10 concentrations reach 1.75 times the standard of 50