This paper approaches the floods of 2015 in Chennai, Tamil Nadu, India, as the consequence of policies, plans and procedures that, over many years, had erased monsoon water and wetness from the city and its imaginary. In order to do this, it examines a number of plans that authorized spatial development in Chennai from the early 20th century onwards. It approaches them as urban cosmograms, in which heterogeneous entities were accommodated, congealed, concealed or expelled in the description of the urban territory and the composition of the urban world. The paper undertakes this analysis in order to deepen understanding of the relations between spatial planning, capitalist urbanization and the more-than-human vitalities of the monsoon. It approaches the flood waters that rose and fell in 2015 as a cosmopolitical situation and cause for thinking, which, putting people in the presence of the monsoon and its potency in new ways, forced them to confront the precariousness of their co-existence with it and experiment with ways to re-compose the urban monsoonal world differently. This discussion draws from Stenger’s notion of cosmopolitics as a mode of collective practice that proceeds in the company of those who would otherwise be likely to be disqualified as having idiotically nothing to propose, including the more-than-human. The paper makes some critical observations about these experiments and concludes by speculating on whether planning itself might be envisaged as a more inclusive, cosmopolitical project.