The present invention correlates to a heterogenous catalyst for both carbon dioxide and carbon monoxide methanation reactions having high activity and long-term  stability, wherein the catalyst has a nano cuboid structure with a perovskite ABO3 material. "A" site contains La to a high extent with other "f" block elements  substitution in trace amount, on another site "B"contains the Ni metal in major and with Fe, Co, and Cu in minor amount. Further, the present invention provides a  sustainable process for the production of methane using a defined catalyst. Advantages of the present invention are that it claims a sustainable approach for both CO and  CO2 methanation reactions as the nano cuboid perovskite type catalysts having high activity and more than 100 h durable stability without any deactivation.