In America, several car hire firms are taken by surprise at the success of their efforts of becoming more environmentally friendly.

Carbon-offsetting programmes are among the most common approaches by car rental companies which have been adopting to cut their environmental impact.

A scheme was launched previously this month which gives those who rent a car with National, Alamo and Enterprise an opportunity to offset the carbon dioxide generated by their rental vehicle.

With the 'Keys to Green' programme, customers were able to make reasonable but optional payments.

The car hire companies then donate the funds collected through the contribution made by customers in the scheme to environmentally friendly initiatives which are aimed at reducing the impact of greenhouse gasses on the planet.

What makes it accessible and popular among a large number of customers is a little extra amount they need to make as carbon-offset fee-only $1.25 more than the normal rental charges.

Another element that makes carbon-offsetting programme popular is that the contribution made by renters matched by the car rental firm, takes the total amount of funds going towards environmental projects to double.

Some amount of the funds collected Enterprise as the carbon offset fees have gone towards research work for wind energy.

Recently, several airline companies have also launched similar programmes as the passengers are increasingly becoming aware of the impact on the environment due to their travel and they are looking for such opportunities.