Hybrid vehicles are the kind of automobiles that cause less or no environment pollution. In practicality, it is absolutely impossible to run an automobile without some kind of pollutant emission. At least, the technological developments so far cannot guarantee such a vehicle, but there are several methods to reduce the level of pollutant that is emitted.

Currently, the worst culprits of environmental pollution among vehicles are automobiles that run on fossil fuels such as petrol, diesel, and gas. That means more than 90% of these at present, are serious offenders of environmental protection. Among the environmental problems, air pollution and damaging effects of the Ozone Layer are the most serious. There have been concerted efforts from various sectors - such as automobile manufacturers, scientists, and governmental regulators - to reduce the green house gas emission from vehicles that run on fossil fuels.

The efforts have been producing good results. Newer models invariably have better emission controls. However, the overall level of green house gas emission has been increasing. The major reason for this is the exponential increase in the number of these cars in use. Over the last decade, the sale of automobiles has considerably increased - not just in the developed countries like the United States and Japan, but also in developing nations like China and India.

Therefore, just reducing the green house gas emission of cars that run on fossil fuels is not sufficient for reducing the level of environmental damage. This realization paved the way for the creation of several types of green vehicles. Examples of such environmentally friendly cars are electric, solar-powered, and those that use hydrogen fuel. Despite the obvious advantages to environmental protection, there are some negative aspects for them. The performance of hybrid cars at present does not compare well to that of cars powered by conventional fuels such as petrol, diesel, or gas. As a result, a kind of hybrid was born. This type of car can run on both conventional fuels and the non-conventional fuel types. Most of the major automobile companies in the world produce the hybrid type green vehicle.

The most commonly used non-conventional fuel is electricity. The market share of battery-powered cars has been expanding steadily. The level of green house gas emission is substantially lower for electric cars. However, in terms of performance, such as acceleration in high speed, these green vehicles pale in comparison with those that use fossil fuels. Therefore, the hybrids that run both on electricity and conventional fuels provide a compromise option between environmental considerations and the desire for better performance.

Solar energy is also used to run automobiles. The mechanism of these cars is similar to that of electric, however, in the case of solar cars, electricity is provided by solar cells. Another kind of green car is the type that uses hydrogen as fuel. More research and innovations are needed to make the performance of these cars to match with that of those using conventional fuels.