Plug-in electric cars currently make up a fairly small percentage of the millions of new vehicles sold globally.

But within the next two decades, they may be the only new cars available for sale in certain countries.

Multiple countries have announced plans to end the sale of new internal-combustion cars as a way to cut carbon emissions.

DON'T MISS: Norway's Goal: All New Cars Will Be Emission-Free By 2025 To Cut Carbon (Aug 2015)

So which one will be the first?

Norway is likely the friendliest nation in the world for electric cars, and it was the first to discuss making all new cars electrically powered (whether via batteries or hydrogen fuel cells).

The Scandinavian country already offers generous incentives to electric-car buyers, and has built up substantial charging infrastructure.

Oslo street scene: Nissan Leaf, Volkswagen e-Golf, Tesla Model S, July 2015

Oslo street scene: Nissan Leaf, Volkswagen e-Golf, Tesla Model S, July 2015

Electric cars already account for an average 24 percent of new-car sales in Norway, but certain politicians are pushing for them to make up 100 percent of new-car sales by 2025.

This goal was first proposed last August by Ola Elvestuen, a member of Norway's parliament and Chair of the Standing Committee on Energy and the Environment.

Norway's major political parties have now agreed to this "complete ban" on new internal-combustion cars, The Independent reported earlier this month.

MORE: India's ambitious goal: all electric vehicles on roads by 2030

The Netherlands is also moving to end sales of new gasoline and diesel cars by 2025.

In April, the Dutch parliament passed a motion to that effect, although it would still have to be approved by the senate to become law.

Hybrids would still be allowed under the proposed rule, and internal-combustion cars sold before 2025 would be grandfathered for operation until the ends of their lives.

Erasmus Bridge, Rotterdam, by Flickr user Martin de Lusenet (used under CC License)

Erasmus Bridge, Rotterdam, by Flickr user Martin de Lusenet (used under CC License)

Like Norway, The Netherlands boasts significant electric-car incentives, and electric cars account for a greater share of sales than in most countries.

Both Norway and The Netherlands also have concentrated populations, meaning short average commuting distances that won't tax shorter-range electric cars.

That's less true of Germany, where electric cars currently account for a relatively low percentage of sales.

Yet Deputy Economy Minister Rainer Baake believes the country should ban sales of new gasoline and diesel cars by 2030.

Baake believes an emission-free car fleet is the only way to meet Germany's goal of cutting carbon emissions 80 percent by 2050, according to Bloomberg.

Smart Fortwo Electric Drive and Mercedes-Benz B-Class Electric Drive at driving school.

Smart Fortwo Electric Drive and Mercedes-Benz B-Class Electric Drive at driving school.

The government also wants to put 1 million electric cars on German roads by 2020.

Right now, electric cars only account for about 0.6 percent of new-vehicle sales in Germany, although an incentives program approved by lawmakers in May could help boost sales.

The country with the most ambitious electric-car goal, though, may be India.

Rather than simply ending sales of new internal-combustion cars, India's government wants to make all cars in the country electric by 2030.

This would hinge on an incentive program that would allow people to buy electric cars very cheaply.

Smog in Dehli, India (by Flickr user Mfield)

Smog in Dehli, India (by Flickr user Mfield)

However, the proposal faces the challenge of instigating mass electric-car adoption in one of the world's most populous nations, and creating the necessary infrastructure to support all of those new cars.

Many Indian homes do not have access to electricity at all, and the country currently relies heavily on fossil fuels to generate power.

But with some of the worst air pollution in the world, India may have the greatest incentive of any country to make all of the cars on its roads electric.

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