The Indian capital, Delhi, is experiencing its most dangerous levels of air pollution in years, with schools banning outdoor playtime for children and the authorities contemplating emergency measures.

In some areas, the level of air pollution is 10 times more than the recommended safe limit.

One of the reasons is the burning of crops by hundreds of thousands of farmers in northern India, as Sanjoy Majumder reports.

Produced by Shalu Yadav/Filmed and edited by Bhasker Solanki