India, Dec. 29 -- The dense haze in Delhi made people go "what the fog!" on Monday as visibility dropped to zero, beginning Sunday evening, in several parts of the city and its adjoining areas like Uttar Pradesh's Noida, Ghaziabad as well as Haryana's Gurugram.

The India Meteorological Department (IMD) issued an orange alert for Monday and a yellow alert for Tuesday, forecasting dense to very dense fog under the prevailing western disturbance that began on December 27.

The cocktail of dense fog and high levels of pollution that has Delhi and the national capital region (NCR) took the Air Quality Index (AQI) on Sunday to the 'severe' category, a spike that stayed on Monday morning also with a 400-plus overall AQI reading in the city as w...