Alfa, whose new MiTo city car boasts emissions of just 129g/km, now has the 11th lowest average emissions out of all car manufacturers selling in Europe after a 10.13 per cent reduction across its range in just 12 months.
The Italian manufacturer, with the help of low-CO2 Fiat engines, has lowered average CO2 emissions to 141.4g/km compared to 157.33g/km in 2009.
All manufacturers must have average emissions of less than 130g/km by 2015 according to EU legislation. So far three manufacturers, including fellow Fiat Group brand Fiat, are under the 130g/km limit.
However, Citroen boasts emissions of 131.64g/km after a 5.57 per cent increase in the past year and Peugeot is not far off with emissions of 136.12g/km.
Alfa Romeo is one of few manufacturers with a significant fall in average CO2 emissions after the fall slowed in the past year. Some believe this is down to the end of scrappage schemes across Europe.
In total, the industry average CO2 emissions improved by just 0.32 per cent in the first half of 2010 from 145.61 to 145.14g/km.
Jay Nagley, Publisher of Clean Green Cars commented, "Car manufacturers are swimming against the tide now that the scrappage scheme has ended. They are going to have to redouble their efforts to meet what is a reasonable overall target."
Although described as reasonable, the target is a long way away from the worst performing brand, Porsche, with average emissions of 239.9g/km.
The average CO2 figures are expected to fall drastically over the next five years for those manufacturers planning hybrid and electric cars.
Vauxhall will launch the electric hybrid Ampera in 2012 and Ford, Renault, Citroen, Peugeot and Fiat have confirmed plans for electric models in the next five years.