"Chinese cities are struggling with flooding in urban, concrete areas.
Sponge cities aim to capture and utilize this rainwater.
Regulation refers to the instruments that public authorities employ to set requirements for citizens and businesses . The distinction between legislative and regulatory instruments is subtle, however, regulatory instruments can be seen as the way to achieve legislative ambitions. As such, regulatory policy has to ensure rules and regulations are formulated and adjusted in the interest of sustainable economic development. 
 OECD. 2010. Regulatory Policy and the Road to Sustainable Growth. Available online via https://www.oecd.org/regreform/policyconference/46270065.pdf