New Delhi remained the world’s most polluted city until Thursday before light showers slightly helped clear up the toxic haze. But what do the experts think? What are the primary causes? Is it vehicular traffic, or farm fires, or the air flow? And what has been the impact on the city and its residents?

With pollution levels soaring drastically beyond recommended global norms, and the Supreme Court reviewing official steps taken by the government, we look at all the official claims and the scale of the public health crisis.

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