The air crisis in Delhi, and large parts of north India, has come to be framed predominantly as a failure of environmental and public-health management. The intriguing puzzle, though, as we've seen in the past 2 days is not the repetitive nature of the crisis but the collective inability to fix -or even substantially mitigate -the problem. NDTV's Parmeshwar Bawa is in conversation with Dr Vivek Nangia, Principal Director and Head of Pulmonology, Max Hospital in New Delhi's Saket, Public Health Expert Dr. Anurag Mehrotra and Senior Program Manager, Vivek Chattopadhyaya from the Centre for Science and Environment for clarity on the medical emergency that's emerging as a result of the toxic air. What protocols should you follow as the PM 2.5 levels are 30 times the World Health Organization's 'safe' level? Delhi still needs to reduce levels by between 55% to 59% to meet national standards for PM 2.5 as per experts - what should Delhi and the national capital region focus on now?