Vehicular emissions in the urban areas are known to contribute significantly to aerosol black carbon (BC) loading to the atmosphere. Quantification of BC emissions is important from the climate research point of view, as the BC aerosols strongly absorb solar radiation. A case study has been carried out in an urban area, Hyderabad, to assess the impact of emissions associated with truck transport on ambient BC concentration. The study was carried out during the recent nationwide truck strike of April 2003. The results indicate a significant reduction in the BC loading associated with withdrawal of the trucks. The decrease was gradual, while the recovery was almost immediate
