The UK saw a 10.7% fall in carbon dioxide emissions last year.
Official figures from the Department for Business, Energy and Industrial Strategy also show that overall greenhouse gases decreased by 8.9% in 2020, compared to 2019.
The analysis suggests that the fall in carbon dioxide emissions was driven mainly by the reduction in transport and business activity during the national COVID-19 lockdown.
Carbon dioxide pollution from transport fell by nearly a fifth while business sector emissions were down 8.7% in 2020.
However, emissions from the residential sector rose by nearly 2%, as people stayed at home to work.
The figures also show carbon dioxide emissions from the energy supply sector fell by almost 12% due to lower demand and the continued phase-out of fossil fuels in power plants.