Photo: Car Free Indonesia
Jakarta’s air quality in Commercial Business District areas currently exceeds the ambient air quality standards for key pollutants (NOx, SO2, PM10 and O3) based on the continuous ambient air quality monitoring stations in DKI Jakarta.
This state of the air causes various respiratory illnesses and disease suffered by public (e.g., hypertension)
To achieve better air quality and enforce the air quality management program in Greater Jakarta (Local Act on Air Pollution Control), we promote the Car Free Day! This is a revolutionary movement that aims to reduce mobile source emission by encouraging the use of alternative transport (non-motorized) and mass public transport.
Walkability Asia 
For more pics of Car Free Day in Jakarta: http://www.flickr.com/photos/34552879@N02/sets/72157625397477554/