Yamuna River: What makes India's most polluted river cleaner once a year?
The Yamuna may be India's most polluted river, but every year, the river gets a bit better during the monsoon. Especially in the Delhi NCR region, where the pollution gets really bad. Increased rain and water pumps in more oxygen into a river that barely has any oxygen once it flows past Delhi's Wazirabad. Before it reaches Delhi, the river isn't in such a bad state. As it flows through the city, around 18 sewage drains empty into the Yamuna. The water quality deteriorates so much that it's difficult for aquatic life to survive. But the government is hoping to change that by 2019