Toxic smog in India and Pakistan has caused air quality in the major metropolitans of Lahore, Multan, Delhi and Chandigarh to deteriorate to toxic levels.

Record-breaking levels of thick, toxic smog that have shrouded eastern Pakistan and northern India since last month can be seen in striking satellite imagery.

The government in Lahore has closed schools and public spaces and shut down factories. Environmental lawyer Ahmad Rafay Alam shares his perspective: "frustrated" but still fighting.

Pakistan’s cities slip under toxic smog as live readings for Lahore show PM2.5 levels 100 times over what WHO prescribes

Lahore and its 13 million residents have now been choking for a week; the air quality index has passed the 1,000 mark repeatedly this month - anything above 300 is considered hazardous. Pakistani officials have scrambled to respond to the crisis - its scale unprecedented even in a city which deals with smog at this time each year.

The satellite images show an extremely heavy grey smog over Pakistan. It stretches into northern parts of India, albeit is lighter than the one over its neighbouring country.

Dense smog hovering over Pakistan's Punjab province and much of India is visible from space, as seen in NASA's satellite images. Asia is grappling with intense air pollution. Both Pakistan and India are experiencing exceptionally dense smog.

Dense smog hovering over Punjab province and much of India is visible from space. It can be observed in NASA's satellite images. Asia is grappling with severe air pollution. Pakistan and India, especially,