5 pp.

All engines are designed and manufactured to run on specified fuel. They will emit substantially more pollutant if the fuel specification is changed and poorly maintained. Fuel adulteration has been practiced in Nepal due to financial incentives arising from differential taxes that are imposed by the government. Fuels (petrol, diesel, kerosene) mixed in different proportion were used to run the engine at low idling and high idling speed and the tailpipe emissions were recorded for each sample mixture and compare with the existing emission standard for in use vehicles. The test results indicated that there is little change in tailpipe emission with the adulterated fuel. But an adulterated fuel when used in petrol engine has significant negative impact on its performance.