The air quality in India’s capital Delhi and adjoining regions continues to be hazardous for several days now, even as a layer of haze engulfs the city.

On Thursday morning, the city’s overall air quality index – which measures PM2.5, fine particulate matters that can clog lungs, and other pollutants – was recorded at 376, which is more than 25 times the limit recommended by the World Health Organization.

Exposure to this level of pollution can cause serious health problems, especially in children and elderly people.

On Wednesday, Delhi government made it mandatory for all government and private institutions to switch to “work from home” for 50% of their employees.

Several other pollution-control measures have also kicked in – such as a ban on old diesel vehicles on Delhi’s roads and construction activities, hybrid classes in schools and no-entry for older vehicles not adhering to fuel efficiency and pollution control standards.

Toxic air is a recurring problem in Delhi and its neighbouring regions in northern India, especially during winters.

The problem is attributed to a mix of factors such as industrial emissions, vehicle exhaust, dropping temperatures, low wind speeds and the seasonal burning of crop stubble in neighbouring states.