Which one of the following is the major constituent of biogas?

Biogas is a renewable fuel produced through the anaerobic decomposition of organic matter, such as farm waste, animal dung, and human waste [1][3]. The primary and major constituent of biogas is methane (CH4), which typically accounts for 50% to 75% of its total volume [4][5]. Methane is the main energy-containing component, making biogas a high-efficiency fuel suitable for cooking, heating, and electricity generation [2]. The second most significant component is carbon dioxide (CO2), which generally comprises 25% to 50% of the mixture [4][5]. Other gases like nitrogen, hydrogen, and hydrogen sulfide are present only in trace amounts [4]. Because methane is the dominant combustible gas, it is considered the major constituent that defines the fuel's thermal efficiency and utility as a substitute for natural gas [2].

Sources

1. [1] NCERT. (2022). Contemporary India II: Textbook in Geography for Class X (Revised ed.). NCERT. > Chapter 5: Print Culture and the Modern World > Biogas > p. 117
2. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > Microbes as a source of biogas > p. 20
3. [4] https://downloads.regulations.gov/EPA-HQ-OAR-2021-0324-0032/content.pdf
4. [5] https://www.sciencedirect.com/topics/engineering/biogas
5. [2] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.1 BONDING IN CARBON – THE COVALENT BOND > p. 60