New Delhi topped a real-time list of the world's most polluted cities compiled by Swiss group IQAir, which put the city's air quality index (AQI) at 640 in the "hazardous" category on Friday. 

With air pollution worsening in New Delhi and beyond, Indian-administered Kashmir decides to step up efforts to combat its own worsening air quality.

A public health emergency has been declared in New Delhi as a choking blanket of smog descended on the world's most polluted capital city.