The document discusses the Yamuna River, one of the major tributaries of the Ganges River in northern India. It notes the religious and socioeconomic significance of the Yamuna River while also highlighting the major sources of pollution degrading its waters, including domestic wastewater from cities, industrial contamination from nearby areas, and toxicity from idol immersions during religious festivals. The document also briefly mentions some projects aimed at cleaning up the Yamuna River to improve its water quality.