New Delhi, Dec. 15 -- Air pollution is choking the national capital of Delhi, and in view of worsening air quality, the Delhi government has issued several instructions to schools on how to hold classes.

On Monday evening, the Directorate of Education issued a circular, revising orders from an earlier one and directing that classes for students from nursery to Class V should be held exclusively in the online mode.

"In view of the prevailing high AQI levels in Delhi, it has been decided that classes in physical modes for students of Nursery to Class V are discontinued until further orders for all Government, Government Aided, and Unaided Private Recognized Schools of Delhi," the order read.

Monday's circular said the present order holds...