Finishing second and third respectively in the table behind hybrid car king Toyota, Peugeot and Citroen ensured the top three was dominated by French manufacturers.
The ranking system, devised by Rank a Brand, looked at green models but also the footprint of manufacturing operations.
Peugeot and Citroen are owned by the same group, the PSA Group, and both scored highly in the complicated process, which involved compiling huge amounts of information to create the final table.
According to Rank a Brand: "A large stack of information on regulations in the automotive industry, the best practices of car brands and information from conversations with auto experts had to be summarized into reliable and sharp questions."
However, the final results will be a boost for both manufacturers, who will be launching their own versions of the rebadged Mitsubishi i-MiEV electric car in the shape of the Peugeot iOn and Citroen C-Zero in 2011.
Citroen also boasts an eco-signature range, the Citroen Airdream+, which can be found on popular models such as the Citroen C3 and C3 Picasso. In the case of the Citroen C3, the Airdream+ model brings CO2 emissions below 100g/km.
This means it is free from both emissions-based road tax and the new congestion charge from 2011.
After Toyota, Peugeot and Citroen, Italian manufacturer Fiat finished fourth in the rankings.
Fiat will have been boosted by the introduction of the ultra-efficient Fiat 500 TwinAir, a two-cylinder petrol version of the retro city car which brings emissions below the magical 100g/km mark.
It is one of the lowest-emitting petrol models on the market and the technology has won a host of industry awards since its introduction earlier this year.