Pie charts of sources of CO2 emissions in London. 2006 total emissions from all sectors, excluding aviation, amounted to 44.3 million tons of CO2. Ground-based transportation accounted for 22% of total emissions in 2006, or 9.6 million tonnes of CO2. Residential accounted for 33% of CO2 emissions, Commercial for 33%, and Industrial for 7%. Of the ground-based transporters, 49% came from cars and motorcycles, 23% from road freight, 11% from ground-based aviation, 5% from bus, and 4% each from taxis/PHVs, Underground, and National Rail.