Which alkane is known as marsh gas?

Methane is the lightest hydrocarbon having one carbon and four hydrogen atoms. Its molecular weight is 16. It is also a fuel gas commonly called marsh gas because it is produced from marshy lands. Some facts about it: 

• Methane is produced when vegetation decomposes naturally within some geographical marshes, swamps.
• The main process behind the production of methane is anaerobic digestion.
• Biogas or Gobar gas also contains 60-70% of methane. 
• Methane is one of the greenhouse gases. Other greenhouse gases are- carbon dioxide, water vapour, nitrous oxide and ozone.
• Methane is produced in the soil during microbial decomposition of organic matter and reduction of CO2 under strictly anaerobic conditions. 

Hence, we conclude that Methane is known as Marsh gas.