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.

With cities in India and Pakistan ranking among the world's most polluted, new technologies must be adopted to tackle dangerous levels of winter smog, environmentalists urge.

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

Residents of India’s capital New Delhi choked in a blanketing toxic smog Wednesday as worsening air pollution surged past 50 times the World Health

But experts caution that the problem goes beyond just agricultural burning. According to India Today, NASA scientist Pawan Gupta points to other significant factors, including dust from the nearby Thar Desert, which combines with emissions from vehicles and factories, adding to the hazardous mix.

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.