Old vehicles continue to be a significant source of air pollution, especially in rapidly growing urban areas across India. Despite accounting for a smaller share of the total vehicle population, aging cars, trucks, and two-wheelers contribute disproportionately to vehicular emissions. Understanding how these older models cause more pollution is critical as policymakers and environmental agencies work toward cleaner and healthier cities.
The primary reason older vehicles pollute more lies in their outdated engine technology and lack of modern emission control systems. Vehicles manufactured before the enforcement of Bharat Stage emission norms (such as BS-IV and BS-VI) often lack essential components like catalytic converters or diesel particulate filters. These components play a vital role in reducing harmful emissions such as nitrogen oxides, carbon monoxide, unburned hydrocarbons, and particulate matter.
In addition to technological limitations, wear and tear over time significantly reduce a vehicle's efficiency. As engines age, combustion becomes less complete, leading to higher levels of unburnt fuel being emitted into the air. Leaky fuel injectors, malfunctioning sensors, clogged filters, and degraded lubricants all contribute to the deterioration of engine performance and a rise in pollution.
Poor maintenance further worsens the issue. Many older vehicles are not regularly serviced or inspected, allowing mechanical problems to go unnoticed. For example, an engine running on old spark plugs or a vehicle with a damaged exhaust system will emit far more pollutants than one that is properly maintained.
Fuel type is also a factor. Older diesel vehicles, in particular, emit larger quantities of particulate matter and nitrogen oxides, both of which are harmful to human health. Diesel engines without advanced filters release black carbon, a major contributor to poor air quality. Moreover, the older the diesel engine, the higher the emissions, especially in stop-and-go traffic conditions.
Studies conducted in major Indian cities have shown that vehicles older than 10 to 15 years are responsible for a substantial percentage of total vehicular pollution, despite being fewer in number. This has led to regulatory measures such as banning 15-year-old petrol vehicles and 10-year-old diesel vehicles in select regions, including Delhi-NCR. Scrappage policies are also being introduced to incentivize vehicle owners to replace older models with cleaner, more fuel-efficient alternatives.
Transitioning to newer vehicles, particularly those that comply with the latest emission norms or run on cleaner energy sources like electricity or compressed natural gas (CNG), can drastically reduce the pollution footprint. In parallel, awareness campaigns are being launched to educate the public on the environmental and health hazards of operating old and poorly maintained vehicles.
In conclusion, older vehicles pose a serious environmental threat due to technological obsolescence, reduced efficiency, and lack of maintenance. As India faces growing challenges related to air quality and public health, phasing out these polluting vehicles is an essential step toward a sustainable and cleaner future.
