Why can't our rivers passing through cities be just crystal clear like Thames in London, Seine River in Paris, Amstel river in Amsterdam, Rhine river in cologne, Sabarmati river in Ahmedabad, Huangpu River in Shanghai ?
Main reason is no Industrial waste is drained in their rivers other reasons are no one there do the laundry in river. Litre in the river, Make bath to buffaloes, Leave floating Lamps, or pour Milk sweets oils in river, even many cooked edible at times, no body leave the dead bodies(Not Just ashes)
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Mostly cities were built on river banks for easy transport of goods. .India is a peninsula country which has more sea ports more convenient to built cities near the sea than river banks. Most of our important cities face the sea ,or are near to the sea , except Delhi......!