Divali was less noisy and polluting for Delhiites this year due to a drive against crackers that violate norms laid down by the government, claims Delhi Pollution Control Committee (DPCC). The concentration of carbon monoxide and nitrogen dioxide in the Delhi atmosphere showed a considerable decline this year compared to the last year's Divali, according to the data prepared by the DPCC. A monitoring of ambient air quality at 40 locations and noise levels at 30 locations on Divali night has shown a comparative decline in Suspended Particulate Matter (SPM) and carbon monoxide concentration at 28 locations.