Bolivia's annual "Day of the Pedestrian and Cyclist in Defense of Mother Earth" in which all but emergency motor vehicles are banned was a monumental success, with people enjoying the immediate benefits of cleaner air.

The idea started in the heavily polluted industrial city of Cochabamba 18 years ago, and spread across the country.  Eventually, the government turned it into a national event, although several cities have car-free days three of four times a year in addition to the nationwide ban.

"Air pollution drops by 60-70 percent because 70 percent of our air contaminants come from vehicles," said Cochabamba city official Soledad Delgadillo.  Environmental campaigner Jorge Martin Villarroel agreed:  "The difference in air quality is noticeable.  (Pollution) drops to almost zero when normally it can rise as high as 100 parts per cubic meter."

Families are especially appreciative of the car ban.  Jesus Romero of Cochabamba said, "We really enjoy that it is so quiet and peaceful without any cars around, and that there is space in the streets for the kids to play." 

The capital city of La Paz uses the event to promote general fitness and participation in sport, and take a break from politics.  "We have so many blockades and demonstrations, we want to encourage a positive citizen takeover of the streets," La Paz official said Jessica Nieto.