National Pollutant Discharge Elimination System (NPDES) is the scheme that was created under the Clean Water Act (CWA) in 1972. This program addresses the problem of water pollution. Under this scheme or permit, municipalities and factories' discharging pollutants into the navigable water is regulated.
Environmental Protection Agency under the CWA permits states, government and authorities to enforce or implement the NPDES program.
So, the correct answer is the National Pollutant Discharge Elimination System.
