Honda has been named the "greenest automaker" in the US in a new study from an environmental group released October 7.

The Union of Concerned Scientists (UCS) awarded the Japanese brand top place in its automaker rankings, which are released every two years and examine the emissions of US automakers.

It is the fifth consecutive time that Honda has topped the list, which features America's eight largest automakers that together account for more than 90 percent of cars and trucks sold in the US.

Toyota and Hyundai achieved a joint second place finish, while Volkswagen came in third.

Chrysler ranked as the most polluting automaker for the fourth time in the last ten years, with UCS saying that it "does what's required by law and not much more" - although the three Detroit automakers (Chrysler, General Motors and Ford) have consistently been placed bottom of the UCS's Automotive Rankings.

Ironically, Chrysler is now owned by Italian car brand Fiat, which was recently judged Europe's cleanest automaker in terms of emissions by automotive analyst JATO Dynamics.

General Motors also came in for criticism, with UCS saying that average smog emissions from its hybrids were actually worse than the combined average of all of the vehicles it examined - both hybrid and non-hybrid.

"To date, GM has largely squandered its hybrid technology by using it to boost power instead of fuel efficiency and pollution control," explained the report's author Jim Kliesch.

"Some models, such as the Chevrolet Volt and Cruze Eco offer promise of new thinking within GM, but the company needs to make improvements across its entire fleet to really move the needle."

Despite the poor performance from some automakers, UCS said that all automakers have become greener since the rankings began in 2000, with the gap between best and worst narrowing considerably.

America's Greenest Automakers

1. Honda
2. Toyota/Hyundai
3. Volkswagen
4. Nissan
5. Ford
6. General Motors
7. Chrysler

Figures from the Union of Concerned Scientists -

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