Don't walk. Don't go to school. Don't breathe too fast.
That's just some of the advice from authorities in Delhi, India this past week, when the smog became so thick that is was described by the local government as a "gas chamber."
Last November, the city experienced some of its worst pollution in decades, and this year looks like it's going to be a repeat. Here's what it's like for people who live in the Indian capital right now:.
The air quality index, which measures the levels of five major pollutants in the air, is above 400 in Delhi. That's the highest pollution category. The air is called "hazardous" at this level.
Man covers his face as he walks to work in Delhi. (Saumya Khandelwal - Reuters)
For comparison, the air in Shanghai is registering around 40 on the World Air Quality Index, and in New York City on Friday night it was 33, according to EPA measurements.
Breathing is worse than inhaling two packs of cigarettes a day.
A street cleaner works in heavy smog in Delhi. (Thomson Reuters)
Just breathing the air is about as bad as smoking 44 cigarettes a day right now, CNN reports.
The levels of smog being recorded right now in Delhi are more than 20 times worse than in Beijing, a city that often deals with heavy pollution.
Vehicles drive through heavy smog in Delhi. (Cathal McNaughton - Reuters)
It's gotten so bad that United Airlines has suspended all its flights into the Indian capital.
United Airlines won't be flying into New Delhi any time soon. (United Airlines)
Nearly 17 million people live in the Delhi region and they've dealt with smog like this before.
New Delhi is blanketed in fall smog. (Cathal McNaughton - Reuters)
The country is now the world's largest emitter of sulfur dioxide from coal-fired power plants.
A man exercises in a park on a smoggy morning in New Delhi. (Saumya Khandelwal - Reuters)
One writer at Quartz India even went so far as to say the smog now "heralds the winter" in his home country.
Conditions are expected to get worse this weekend.
A man covers his face as he walks to work, in Delhi, India, November 7, 2017. (Reuters)
The haze is also wafting over Pakistan where Reuters reports road accidents are up and 15,000 people have been hospitalized. Authorities are planning to use fire trucks to spray down parts of the Indian capital, which they hope will help clear the air.
It's harvesting season in the country and some farmers are lighting crops on fire, adding to the smog that was already in the air from cars and coal-fired power plants.
People cross the road in Delhi. (Thomson Reuters)
Often after rice and wheat stalks are chopped down in the fall, farmers will set their fields ablaze. The slash and burn technique helps planters clear their fields quickly and gets the soil ready for fresh plantings.
It's all part of a much larger epidemic. Globally, pollution is now killing more people than wars, obesity, smoking, or malnutrition.
(Saumya Khandelwal - Reuters)
A study published in the Lancet last month said the environmental contamination is now responsible for one in six deaths worldwide.