In the past 20 years there has been an explosion of growth in Guadalajara and today it is Mexico’s second-largest city.

Between new textile industries moving in, technology companies opening offices and the draw of overall economic vitality, the population has skyrocketed.

Current estimates suggest that more than four million people live there. And the estimated number of cars is nearly two million. It is considered to be one of the most densely populated cities in Latin America as well as one of the most polluted.

Though heavy industry accounts for a significant part of the pollution, the majority comes from car and truck congestion.

The city currently has a higher index of cars per inhabitant than Mexico City which has an estimated population of 20 million.

According to official figures, the number of vehicles in the Guadalajara Metropolitan Zone has tripled from 509,566 vehicles in 1997 to 1,557,194 automobiles in 2009. It is estimated that 350 vehicles are added to city streets daily.