New Delhi has become the world's most polluted major city, often surpassing Beijing.

A choking blanket of smog that's descended on the Indian capital for weeks has caused a public emergency. 

To protect residents and reduce pollution, authorities have temporarily closed schools, construction sites and power plants.

Despite these measures there has been no significant impact on the smog.

But as TRT World's Shamim Chowdhury reports, some businesses began using a new technology to clean up the air in offices.