Q. Assertion : The concentration of methane in the atmosphere has more than doubled in the last years.
Reason : Wetlands and rice fields are the major sources of methane.

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Solution:

Methane is a green-house gas. The main sources of it are catle dung, rice paddy fields, wetlands, burning of the biomass and mining of coal and mineral oil. Roots of rice plant's capture methane from muddy surroundings and transport it through the plant's vascular system to the atmosphere. According to an estimate, around million tunnes of methane are released annually.