Prospects of inspection and maintenance of two-wheelers in India.

Two-wheeler vehicles in Delhi, India--roughly 70% of the total vehicle fleet--are responsible for a significant portion of the city's vehicle emissions and petroleum consumption. An inspection and maintenance (I/M) program that ensures vehicle emission control systems are well maintained can complement other emission reduction strategies. This paper presents the initial findings of extensive data collected on vehicle characteristics and emissions for two-wheeler vehicles operating in Delhi in a series of I/M camps conducted by the Society of Indian Automobile Manufacturers and various partners in late 1999. The analysis shows idle HC and CO emissions measured in terms of parts per million (ppm) and volume % (vol %), respectively] in a slow declining trend with subsequent model years, reflecting tighter emission standards and more advanced emission technologies. The I/M benefits--3 vol % and 39% reduction in idle and mass CO, respectively; 40 vol % and 22% reduction in idle and mass HC, respectively; and a 10-20% increase in fuel efficiency--were higher than those reported in the literature. Although these benefits are substantial, any implementation strategy needs to consider cost-effectiveness. In the present study, only 10% of vehicles--contributing 22% of the total vehicle emissions--failed the idle CO standard. Fleet emissions data variability necessitates a large sample size to develop a baseline for the vehicle fleet, but a smaller, scientifically designed sample and better data collection quality could periodically track the benefits at future camps.