Delhi’s air quality improved slightly on Wednesday, a week after it plummeted to the dangerous “severe” category and led to a public health emergency. Despite the minor improvement, the air quality in Delhi is still a health hazard.

At 9 am on Wednesday, the Air Quality Index reading in the Capital was 316 on a scale of 500 – the “very poor” category, according to Central Pollution Control Board data. On Tuesday, the air quality reading was 308. The index had hit a peak of 486 on November 9.

An Air Quality Index reading of up to 50 is considered “good” and up to 100 is considered “satisfactory”. A reading between 301 and 400 is ranked “very poor” on the index and above 400 is “severe”, which means the air is dangerously filled with pollutants.

Falling temperatures and changing wind patterns are helping clean the air, experts said.

“High altitude winds that bring pollutants from outside have calmed down,” Gurfan Beig, project director of System of Air Quality Weather Forecasting, told the Hindustan Times. Beig said pollutants are being flushed out as surface-level winds are gathering speed.

Rain in parts of Rajasthan, Punjab and Haryana has also helped Delhi’s air quality improve, said Sathi Devi, head of the National Weather Forecasting Centre, according to The Hindu. “Strong winds will blow towards the city from the north west by Friday,” Devi said, adding that this will help further improve the air quality.

Safar has forecast a further dip in particulate matter levels in Delhi’s air over the next three days.