The increase in urban ecology research in the social sciences since the 1980s can be explained as an outcome of contemporary urbanization. From an understanding of the commons as a rural artefact, this concept has expanded to include urban spaces and practices. This is significant for countries like India, which are supposed to experience huge urban growth in the coming decades. The emergence of peri-urban interface, where rural and urban features tend to coexist, will be one crucial aspect related to this pattern of urbanization. While striving to reinvent themselves as utopias for investors, entrepreneurs and consumers, like their counterparts in the 'global South', Indian cities are consuming peri-urban ecological commons that are not only critical to urban economic production and cultural vibrancy but also crucial for ecological sustainability of cities and their surroundings. Applying temporal trajectories and political ecology framework, this article looks at transformations of wetlands at the eastern periphery of Kolkata, a process which not only recycles the city's waste, but also produces vegetables, crops and fishes, providing livelihood to poor communities. We explore a core-periphery metabolism that determines socio-economic and ecological sustainability and engages into complex interactions among varieties of environmentalism that shape the city's urban transition.