Hindu devotees perform rituals as they stand amidst the polluted waters of the river Yamuna covered with a layer of foam, on the occasion of the Chhath Puja festival in New Delhi, India. An enormous stretch of one of India's most sacred rivers, the Yamuna, is covered with toxic foam, caused partly by high pollutants discharged from industries around the national capital. Still, hundreds of devotees offer rituals in its frothy and toxic waters, sometimes even immersing themselves in the river for a holy dip, to mark special occasions and festivals.