A 1995 estimate by the Reuters news agency puts the total pollutant emissions at around 63,000 tonnes per year. Furthermore, the number of vehicles in Nepal, especially in Kathmandu, is expected to grow substantially in the years to come because of increasing levels of personal income in the valley. The economy of Kathmandu is growing rapidly, as it is fuelled by the current economic reform programmes, the opening of the economy, privatisation and a general increase in the cash economy. Hence as incomes are expected to continue to rise in Kathmandu, there will be increased vehicular ownership, and consequently more pollution, unless appropriate measures are taken. Only leaded gasoline, which is frequently adulterated, is available in Kathmandu, and a large percentage of heavy vehicles run on diesel.
Fuel sold in Nepal is of very poor quality, similar to that available in India and Pakistan.
The current lead content in gasoline sold in India and Pakistan ranges from 0.42 grammes per litre to 0.82 grammes per litre, which is among the highest in the world. Leaded gasoline emits lead to the air, resulting in a significant cause of decreased IQ among children, increased incidence of high blood pressure among adults, and can be highly detrimental to unborn children. Similarly, high sulphur content in diesel contributes to environmental deterioration both directly and indirectly. Directly, it is emitted in the environment in the form of SO2 and those not emitted as SO2 are converted to various metal sulphates and to sulphuric acid, both of which are emitted in particulate form. Since the diesel fuel sold in Nepal is similar to that sold in India and Pakistan, it is probably high in sulphur content as well as lead.