The day brought more bad news: the smog isn’t going anywhere, at least for the next few days, experts warned.

In south Delhi’s RK Puram, particulate matter 2.5 or PM2.5 (particles smaller than 2.5 microns in diameter) peaked to an alarming 985 µg/m3, against a safe limit of 60 µg/m3, at 6am and stayed that way till 11.30am. Similarly, PM10 ranged between 500 and 600 µg/m3 in the last 24 hours, against an acceptable 100 µg/m3.

These particles are fine enough to lodge deep in the lung and blood tissues, and cause diseases ranging from stroke to lung cancer.

The US embassy’s Air Quality Index, which converts PM2.5 data and places them on a scale of 0 to 500, showed a reading of 274 in Chanakyapuri at 9pm — falling in the ‘very unhealthy’ 201-300 range, according to US standards.

The smog — a constant presence in Delhi over the last few days — is a result of seasonal burning of crops in neighbouring states and the city’s very high vehicular pollution, all trapped in by a lack of wind movement.

“There is a possibility of a marginal intensification of the smog in the next three to five days, till the western disturbance moves towards the hills of the north,” said RK Jenamani, director in-charge at the IGI Met Centre.

“There is a direct increase in incidence of heart disease and respiratory illness with increased exposure to air pollution, both outdoors and indoors. There’s a rapid decline in lung function and lung capacity among people with prolonged exposure to polluted air. It can even turn fatal in some cases,” said Dr Randeep Guleria, who heads the pulmonary medicine department at AIIMS.

He advised people not to delay seeing a doctor “if symptoms like difficulty in breathing, wheezing and persistent cough appears”, adding, “Winters are especially bad as polluted air gets trapped closer to the surface, and we are forced to breathe it.”