Delhi, India's vast central metropolis and the sprawling seat of government, has the deadliest air of all the world capitals - routinely exposing millions of its inhabitants to a shocking range of life-threatening diseases, which in turn cause thousands of fatalities every year. So why is Delhi's air so polluted? And what if anything is being done to clean it up? We asked journalist Neha Mehta, who was born and raised in the city, to find out. - Subscribe to our channel: http://aje.io/AJSubscribe - Follow us on Twitter: https://twitter.com/AJEnglish - Find us on Facebook: https://www.facebook.com/aljazeera - Check our website: https://www.aljazeera.com/