"Landfill gas" refers to the gas that is produced when waste decomposes in a landfill. It is made up of different gases like methane and carbon dioxide. Full definition
The use of landfill gas for energy purposes or its destruction by means of an ordinary flare is often not possible due to the low methane concentration. (firstclimate.com)
The 2012 - 13 progress report showed a 4 % reduction in community carbon emissions, in part from upgrades to the city's landfill gas capture systems. (c40.org)
Management of safety and health risks arising from landfill gas emissions. (environment.gov.au)