Delhi pollution watch: Wind speed clears smog, but air remains toxic

On Monday, wind speed picked up, dispersing the smog and improving visibility. But pollution levels in Delhi still continue to be severe and air quality remains poor.

Breathless in Delhi Updated: Nov 08, 2016 11:58 IST
Ritam Halder
Ritam Halder
Hindustan Times
Delhi pollution,Air Quality,Smog
A man wears a mask to protect himself from the pollution as he drives a motorbike in Delhi. (REUTERS)

Pollution levels continued to be severe on Monday as the city woke up to another smoggy morning. According to SAFAR, nearly all stations in Delhi had Air Quality Index at a maximum of 500.

However, the sun came out as the day progressed and the city’s air quality marginally improved as wind speed picked up dispersing the pollutants and the thick cover of haze that had kept the city shrouded for nearly a week.

Monitoring agency System of Air Quality and Weather Forecasting and Research (SAFAR) showed 24-hour-average (rolling) level of respirable pollutants PM 2.5 and PM 10 in the “severe” category at 622 and 808 micrograms cubic metre respectively at 5pm.


The 24-hour average Air Quality Index (AQI) recorded by the Central Pollution Control Board (CPCB) was 423, as against Sunday’s 497, which was the season’s worst.

“The air quality has improved due to increase in wind speed, although the wind direction continues to be north-northwest. By Wednesday, wind speed is likely to increase some more and wind direction will also be easterly which is likely to further improve the air quality and turn it very poor from severe,” project director of SAFAR Gufran Beig said.

“Winds are coming from north-north west, the areas where biomass burning is taking place, from Thursday. Friday changed it a bit thereby bringing a bit of relief but then again it got worse,” he said.

The wind direction is important from the point of view of stubble burning in Punjab and Haryana which falls in the North West region. Wind blowing from that direction brings pollutant-laden smoke to Delhi.

The Delhi Pollution Control Committee’s (DPCC) real-time readings displayed a downward trend cutting across its monitoring stations.

The city’s pollution hotspot Anand Vihar had a PM10 reading of 1,640 micrograms per cubic metre at 4am. It came down to 580 by 5pm while PM2.5 was at 145 micrograms per cubic metre.

At Punjabi Bagh, PM10 came down to 214 micrograms per cubic metre at 5pm from a high of 1270 recorded at 10am.

The smog that had engulfed Delhi for the last week lifted, at least for a while, after an increase in air flow dispersed particles. Experts say it may remain relatively clear for a while but particulate matter is still much higher than safe limits.


RAIN: Delhi plans to replicate Beijing’s experience with artificial rain to clear heavy smog. However, it is not clear how often authorities in Beijing use the technology to clear smog or whether it is effective at times of chart-bursting pollution.

Winds blowing from north, northwest directions started at 2pm and reached a speed of 16kmph in certain areas by 2.30pm
STEP 2: Wind persisted through most of the day, at an average speed of 8-12kmph. This helped disperse the smog.
STEP 3: From 200m at 8.30am, the visibility improved to 1800m at 2.30pm--30minutes after the wind picked up.


The measures taken by the government may bring some relief to the citizens but this is frankly too little and too late. What helped Delhiites on Monday was not the implementation of these measures but the proactive winds. What Delhi needs at the moment is a national action plan and infrastructure improvement.
- Sunil Dahiya from NGO Greenpeace.

With wind speeds expected to pick up in the coming days, the smog will continue to clear, though a mist/ shallow fog is predicted for Tuesday morning. Wind at a speed of 10-15 km/hr is expected, which will blow away more smog.
According to SAFAR, Tuesday, too, is likely to have "severe" air quality. However, after three days, things will improve to "very poor". Even though Delhi experienced relatively clear skies on Monday, the air quality at most monitoring stations was recorded as severe.

First Published: Nov 08, 2016 11:58 IST