Explanation:

One of India's holiest rivers - the Yamuna - is coated with toxic foam, adding to the woes of New Delhi residents already enduring a blanket of thick smog over the capital.The city government has blamed the blight on "heavy sewage and industrial waste" discharged into the river from further upstream last week. But it didn't stop several Hindu worshippers from taking a dip in the river to mark Chhath Puja, a four-day festival to offer prayers to the sun.