Name any one greenhouse gas and its possible source of production on a large scale

Name any one greenhouse gas and its possible source of production on a large scale. What are the harmful effects of it?

Carbon dioxide is a major greenhouse gas. Various human activities such as combustion of fossil fuels, electricity generation, transportation and industries are sources of its large scale production. Excess of $C0_2$ is harmful and considered as a pollutant. It is because it traps longer wavelength IR radiations reflected by earth’s surface, thus causing global warming.