Delhi breathes better, air remains moderately polluted

From the "severe" AQI reading of 435 on November 15, the air in the capital improved to "poor" (221) on November 16 and "moderate" (171) on Tuesday

Delhi’s air quality continued to be in the "moderate" category on Wednesday morning as favourable meteorological conditions and the reduction of farm fires helped the capital to breathe better. With a marginal deterioration from Tuesday, the Air Quality Index (AQI) value stood at 180 at 6am on Wednesday.

The banks of the Yamuna engulfed in smog during the morning in New Delhi. (Sanjeev Verma/HT PHOTO)

From the "severe" AQI reading of 435 on November 15, the air in the capital improved to "poor" (221) on November 16 and "moderate" (171) on Tuesday. An AQI reading 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".

Scientists have said that due to high wind speeds throughout the week and the negligible stubble burning activity, the air quality is expected to remain in the range of "moderate" to "poor". VK Soni, of India Meteorological Department (IMD)’s environment monitoring research centre, said that the average wind speed on Tuesday was around 15kmph, which helped disperse the pollutants in the air.

"Our forecast is that even on Wednesday, the air quality will remain in the moderate range. Even though the wind direction changed to north-westerly on Tuesday, because the stubble burning activity is almost over, its impact on Delhi"s air quality was almost negligible on Monday and on Tuesday," he said.

According to the Union ministry of earth sciences’ air quality monitoring centre, System of Air Quality and Weather Forecasting and Research (Safar), the air quality can slip into the poor category on Wednesday.

"The AQI is likely to marginally deteriorate and in moderate to the poor category is forecasted for Wednesday. AQI is forecasted to further deteriorate to the higher end of poor to lower end of very poor category on November 19 and 20," the Safar bulletin said on Tuesday.

Meanwhile, the temperatures are likely to drop in the national capital this week. According to the IMD forecast, the capital is likely to have a foggy Wednesday morning with minimum temperature dropping to 11 degrees Celsius and maximum temperature around 26 degrees Celsius.

On Tuesday, Delhi’s minimum temperature, recorded at the Safdarjung observatory, which is considered the official reading for the city, was 13 degrees Celsius – one degree above normal. The maximum temperature was 26 degrees Celsius – two notches below normal.

Kuldeep Srivastava, head of IMD’s regional weather forecasting centre, said that widespread snowfall in Jammu and Kashmir, Himachal Pradesh, and the upper reaches of Uttarakhand will lead to a fall in the minimum temperature by around 2 to 4 degrees Celsius over northwest India in the next few days.

"The winds have shifted to north-westerly from Tuesday so cold winds will be blowing from the western Himalayas, where snowfall has just happened. We are expecting minimum temperature to drop to around 10 degrees Celsius in the next couple of days," Srivastava said. IMD scientists have also said that the minimum temperature in Delhi may fall to 9 degrees Celsius by November 22.