Vision is the most blessed of the senses at the Kumbh Mela. Not long after you arrive at the fair, a ceaseless blare of lost-and-found announcements on the tannoys benumbs your ears. A smelly mix of drying urine and log-fire overwhelms your nostrils. A few days of street food makes a leathery toast of your tongue. A few weeks of jostling amid the world&rsquos largest crowd tends to leave a colourful mark or two on your skin. And yet, you do not want to close your eyes.