Air quality in Delhi, India, fell into the "poor" range on Wednesday for the first time this season, according to The New York Times, TBS News and The Week. Officials started the first stage of an emergency plan to fight the pollution.

Delhi's haze returns every winter, the Times reported. The city is India's largest metropolitan area.

The air quality index, or AQI, stood at 179 on Tuesday, which is rated moderate, the Times reported. It rose to 244 by 2 PM on Wednesday, the Times said, citing a government notice. TBS News and The Week reported a reading of 245. TBS News and The Week said that was the highest in 100 days.

India rates AQI readings from 201 to 300 as poor, TBS News reported. Readings above 400 are severe.

The Commission for Air Quality Management started Stage I of its action plan across Delhi, TBS News reported. The first stage limits construction, bans coal and firewood as fuel and aims to ease traffic jams, the Times said.

Air quality is likely to stay poor until at least October 23, TBS News and The Week reported, citing an early warning system. The outlook for the six days after that is also poor.

Traffic in the city was the biggest source of pollution on Tuesday, at 20.5%, TBS News reported. Burning crop waste on farms made up as much as 8%. The drop in air quality came a day after a festival when large figures were burned across Delhi, TBS News said. But no direct link has been found.

The Week shared tips from Max Healthcare, a hospital group. It advised people to spend less time outdoors, use air purifiers and wear masks. Warning signs include burning eyes, a scratchy throat, coughing and shortness of breath. People who feel sick should see a doctor, The Week said.

What we know: Delhi's air hit the "poor" range on Wednesday, and Stage I limits are in place.
What we don't: How bad the air will get as winter sets in.