The anaerobic breakdown of organic material within the landfill creates a tremendous amount of greenhouse gases, mainly carbon dioxide and methane. Methane, having 28–34 times the potential for global warming compared to carbon dioxide, enhances climate change and poses risks to the health of people in contact with it. The harmful effect of landfill emissions on the environment and human health underscores the urgency of adopting better waste management practices and efficient gas collection systems. The present study is an effort to estimate methane emissions from the municipal solid waste (MSW) dump site of Lucknow, India, using the LandGEM 3.03 version model. The research is carried out for 2015–2039 years in order to arrive at temporal trends of methane emission. Preliminary results suggest possible methane production and LFGs production to be 37.24 Gg/year and 139.4 Gg/year, respectively, towards the closing years of the research study. The average landfill gas and methane emission has been estimated at 78.96 Gg/year and 21.09 Gg/year, respectively. The study uncovers the necessity of having suitable waste management methods in order to stop the emission of greenhouse gases and also add to the evidence of energy recovery from landfill gas. The study adds to the field of knowledge on methane emissions in cities and calls for the adoption of eco-friendly waste management methods in order to stop environmental issues associated with landfills.