The air quality in Delhi remained in the “very poor” category for the second day on Sunday, PTI reported, citing data from the Central Pollution Control Board. Authorities have warned that the air will worsen in the next few days, PTI reported.

The overall Air Quality Index of Delhi was recorded at 301, according to the pollution control board. By 1 pm on Sunday, however, the level was at 293, with PM 2.5 and PM 10 particles being the main pollutants. PM2.5 is the presence of particles in the air with a diameter of less than 2.5 micrometres.

According to data from the Centre-run System of Air Quality Forecasting and Research, the overall Air Quality Index of Delhi on Sunday was 321, also in the very poor category. System of Air Quality and Weather Forecasting And Research has forecast “poor” air quality over the next week.

A haze had engulfed the National Capital Region on Saturday, with the area recording its worst air quality of the season at 326. Anand Vihar, Mundka, Narela, Dwarka Sector 8, Nehru Nagar and Rohini were all in the “poor category”.

An AQI between 0 and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

“We are issuing directions for specific locations where pollution levels are high,” The Times of India quoted Sunita Narain, a member of the Environment Pollution Control Authority, as saying on Saturday. “A meeting may be held next week if the levels reach close to severe.”

NASA satellite images from Friday showed high aerosol optical depth over the northern states and the Himalayan foothills over the past couple of days. High aerosol optical depth are an indirect proxy for air quality since solid and liquid particles in polluted air block sunlight and lead to smog. NASA imagery also showed countless spot fires in Haryana and Punjab, PTI reported.

“Northern India and the foothills are affected by high aerosol levels,” said an unidentified Met department official. “Unless there are strong winds to drive these aerosols away, they will remain accumulated. During Diwali, the situation will obviously deteriorate further unless strict restrictions are placed on firecrackers.”

Delhi Chief Minister Arvind Kejriwal had tweeted that the Capital would soon become a “gas chamber”. “V [sic] sad that Central, Punjab and Haryana Govts did absolutely nothing for the farmers. As a result, the farmers will suffer on one hand and Delhi will become a gas chamber soon.”

In September 2017, the Supreme Court suspended the sale of firecrackers in Delhi and NCR till November 1, 2017 after air quality dipped during Diwali the previous year. However, officials in the pollution control board said they have not restricted the use of firecrackers this year because they are awaiting a Supreme Court verdict on a petition calling for a nationwide ban on the sale and use of firecrackers during Diwali.