Which of the following rivers is significantly affected by pollution and poses serious environmental challenges?

The Ganges River, a sacred waterway in India, is notoriously one of the most severely polluted rivers globally. It faces immense environmental challenges due to the discharge of untreated sewage, industrial waste, agricultural runoff, and religious offerings. This extreme pollution poses significant health risks to millions of people who rely on the river for drinking, bathing, and irrigation, and causes extensive ecological damage. While other major rivers like the Amazon, Nile, and Thames also face environmental concerns, the Ganges stands out for the sheer scale and severity of its contamination and its profound impact on human and ecological well-being.