While the rejuvenation of India's rivers is a major future challenge for sustainable urban development, large-scale riverfront development projects across India indicate that the riverbed is often seen almost exclusively as real estate. In Delhi, a series of urban mega-projects has been realized on the river's floodplain, which almost simultaneously had been cleared of large slum settlements. By focusing on the environmental dimensions, discourses and legal conflicts, the case study contrasts the slum demolitions and the development of two intertwined mega-projects (the Akshardham Temple complex and the Commonwealth Games Village). Grounded on Ananya Roy’s (re)interpretation of informality as “a mode of urbanization”, the paper argues that urban mega-projects in India should be interpreted as intentionally created zones of exceptions embedded in a calculated urban informality.