Photos: New Delhi chokes on smog A Delhi policeman stands guard at the war memorial India Gate engulfed in a thick smog in New Delhi, India, on November 6, 2016. Hide Caption 1 of 7

Photos: New Delhi chokes on smog Protesters wearing protective masks take part in a rally urging immediate action to curb air pollution in New Delhi on November 6, 2016. Hide Caption 2 of 7

Photos: New Delhi chokes on smog Schools in the Indian capital have been closed for the three days as the city struggles with one of the worst spells of air pollution in recent years. Hide Caption 3 of 7

Photos: New Delhi chokes on smog Young Indian runners take part in the New Delhi 10K Challenge amid heavy smog on November 6. Hide Caption 4 of 7

Photos: New Delhi chokes on smog Indian women walk as smog envelops the Jama Masjid Mosque in the old quarters of New Delhi on November 3. Hide Caption 5 of 7

Photos: New Delhi chokes on smog Indian commuters walk through the smog in the old quarters of New Delhi. Hide Caption 6 of 7