Delhi's air quality worsens to 'severe'; thick smog envelops capital

The dip in air quality comes a day after pollution levels had marginally improved on Wednesday when the AQI was in the 'poor' category.

An AQI reading of 0-50 is considered 'good,' followed by 'satisfactory' (51-100), 'moderate' (101-200), 'poor' (201-300), 'very poor' (301-400), and 'severe' (401-500).

Thursday marked the first time that Delhi's air quality worsened to 'severe' this season.

According to the India Meteorological Department (IMD), wind speeds had dropped on Wednesday which led to the accumulation of pollutants.

Calm winds and low temperatures trap pollutants close to the ground.

The System of Air Quality and Weather Forecasting And Research (SAFAR) showed the share of stubble-burning in Delhi's PM2.5 concentration was 18% on Wednesday, marginally down from 23% on Tuesday—the maximum this season.

The head of IMD's environment monitoring research center, VK Soni, said the air quality will likely deteriorate further on Thursday.

However, the air quality will improve significantly from Friday to Sunday as wind speeds are likely to reach 15kmph on Friday, leading to better dispersion of pollutants, Soni said.

"Till Sunday, the forecast is that we will see an improvement in air," he said.

Delhi Environment Minister Gopal Rai had said on Wednesday that only "green" firecrackers can be manufactured, sold, and used in the national capital.

He had also said that the Delhi government will launch an anti-firecracker campaign from November 3.

The government has requested people not to burn crackers at all since rising pollution levels can also increase the risk of COVID-19.