1. Introduction Since the EARTH SUMMIT (United Nations event) was launched in Rio de Janeiro, Brazil, in 1992, the concept of sustainability has exerted a significant influence on policy at the regional level. Sustainable urban development has also become an influential localized strategy for global sustainability. Mumbai, a major city that has taken several vital steps towards developing the growth and needs of the city and the concept of sustainable development, which has become a priority in the modern scenario. Are these measures enough to sustain these cities beyond fossil fuel depletion? Energy Transition Priorities The post-oil era in India would be very challenging and unpredictable, especially for cities and suburban areas around state capitals. The obstacles of these settlements are enormous compared to rural areas. Mumbai, being the financial capital of the country, will face the tough challenge and effect of fending off its meltdown during the post-oil era. To overcome this obstacle we must focus on how to sustain ourselves after vaporizing fossil fuels. In the 1930s only 1/10 of the population lived in cities, now over 50% of the world's population lives in cities. We live in a hyperconnected world; “GLOBALIZATION” is the word of the day. What happens in one city really affects another city. During the era of cheap oil, these cities and urban centers grew rapidly and now consume more than 75% of the world's energy and emit 80% of the world's greenhouse gases. constitute 80% of urban humanity”Urbanization, which is largely due to natural growth, is inevitable. However, the core process of the revenue model is incorporated into the site. Thus making the community self-sustainable.6. ConclusionThese radical changes in the city atmosphere will create fear among city dwellers. However, if we want to achieve a sustainable future, changes need to happen. Overcoming the fear of change would be difficult, but we have no options. The longer we delay in acting. The consequences would be inevitable. These changes must take their own course based on the topographical conditions and culture of the city. We cannot apply all technologies in all cities. We must respond to current conditions and we must consider developments over the years. The drafting of a phased master plan should have a symbiotic relationship with the existing urban fabric and adaptations of new technologies should not have a negative impact.