Pollution of the Ganges, the largest river in India, poses significant threats to human health and the larger environment. The river, which is severely polluted with human waste and industrial contaminants, provides water to about 40% of India's population across 11 states, serving an estimated population of 500 million people, which is more than any other river in the world.

Today, the Ganges is considered to be the fifth-most polluted river in the world. Raghubir Singh, an Indian photographer, has noted that no one in India spoke of the Ganges as being polluted until the late 1970s. However, pollution has been an old and continuous process in the river by the time people were finally acknowledging its pollution. Stretches of over 600 km (370 mi) were essentially ecologically dead zones.

A number of initiatives have been undertaken to clean the river, but failed to deliver desired results. After getting elected, India's Prime Minister Narendra Modi affirmed to work on cleaning the river and controlling pollution. Subsequently, the Namami Gange project was announced by the government in the June 2014 budget. An estimated Rs 2,958 Crores (US$460 million) have been spent until July 2016 in various efforts to clean up the river.