“I don’t think it’s ever been so bad in Delhi. I’m very angry that we’ve had to come to this.”

Public health officials in Delhi, India have declared a public health emergency because toxic smog levels have reached absurd heights.

How absurd?

Well, it turns out that inhaling the air in Delhi over a 24-hour period is the equivalent of smoking 45 cigarettes per day.

City officials closed all schools on Tuesday and advised that children should stay indoors. The next day authorities ordered all constructions projects to cease and barred trucks from entering the city. Next week the city is expected to implement a partial ban on private vehicles.

Doctors in the city have reported a surge in patients coming in with chest pain and breathing problems.

“The number of patients have increased obviously,” Deepak Rosha, a pulmonologist told CNN. “I don’t think it’s ever been so bad in Delhi. I’m very angry that we’ve had to come to this.”

The pollution in Delhi mostly comprises vehicle exhaust, road dust, and garbage and crop fires, experts say. The smog is particularly bad during winter months.

Delhi’s chief minister took to Twitter this week to weigh in on the situation in stark terms, calling the city “a gas chamber.”

Delhi has become a gas chamber. Every year this happens during this part of year. We have to find a soln to crop burning in adjoining states

— Arvind Kejriwal (@ArvindKejriwal) November 7, 2017

But that was when the Air Quality Index was at 800 micrograms per cubic meter. Now it’s reached 999, which is the maximum amount air monitors can register. The AQI is based on the concentration of fine particulate matter in the air, or PM2.5 per cubic meter. These tiny particles measure less than 2.5 micrometers in diameter, which means they are small enough to be inhaled deep into humans’ lungs and find their way into other vital organs.

The 999 reading is far above what is considered safe by the World Health Organization. As far as the WHO is concerned, air that registers 25 or below on the AQI is regarded as safe. The current level in Delhi is 40 times beyond that.

Approximating pollution levels to cigarette smoke was first advanced by Richard and Elizabeth Muller at Berkeley Earth, a non-profit dedicated to study the effects of climate change.

In an effort to discourage private vehicle travel, Delhi officials announced that commuters would be able to travel on public buses at no cost from November 13 to 17.