Mexico City, Mexico - This has been a common scene around the Mexico City underground lately: students jumping over turnstiles or crawling under them, and journalists reporting on this new social movement.

Last Friday, the price of a metro ticket went from 3 to 5 pesos; a sharp 66 percent rise for commuters’ transportation budget. The metro ticket now costs the equivalent of 7.6 percent of the daily minimum wage.

Workers who use two tickets daily to go to work and back, are using 15 percent of their daily income towards transportation - a figure which makes the Mexico City underground proportionally one of the most expensive in the world.

Confrontations are going on between metro employees and angry users who have joined student protests. The Federal District measures over 700 square miles and has the largest concentration of automobiles in the entire country. At rush hour, it is much quicker to get around by metro rather than going by car and risking endless traffic jams.

Until the late 1990's, Mexico City was one of the most polluted capitals in the world. Traffic and transportation remain constant challenges for its 23 million inhabitants. Authorities claim the underground network needs urgent renovation to stay functional for its 8 million users.