Mumbai has not accomplished the level of green space in their city structurally like Zurich and Vienna have, and for a number of reasons as it relates to its growth and urbanization. Zurich and Vienna have both consciously devised public spaces, transit environments, and walkable neighborhoods.
Vienna has clean air, Zurich has clean waterways, and Singapore has been a city that has attempted to combine city planning focused on environmental sustainability, while Mumbai has significant air pollution problems, few public spaces, and high population density, making it a very congested city.
Singapore has a great public transit system, with connections to every part of the city. While Mumbai has a very underdeveloped transit system, where, once again, the emergence of the metro and expanding infrastructure doesn't include the supporting infrastructure and ridership capacity that are needed.
Mumbai, Vienna, and Zurich stress the need for striking balances between work and personal life and offer generous areas of leisure, while Mumbai's frenetic pace of life poses difficulties for maintaining work-life balance and enjoying a quality of life.