Will Delhi become a gas chamber again?

The national capital has been in the ‘severe’ AQI category since Diwali night

By Avikal Somvanshi
Published: Tuesday 29 October 2019
Smog over Delhi. Photo: @zafarabbaszaidi / Twitter

The 24-hourly PM2.5 concentration slipped into the ‘severe’ category at 3 AM on October 28, and is in that category even as I write this. That is almost 40 hours (6 PM on October 29).

The official threshold for declaring emergency is 48 hours of continuous ‘severe’ category of air quality (See Graph 1). If the hourly concentration data is looked into, it becomes amply clear that pollution is only dissipating when the wind speed picks up (See Graph 2).

And the last few hours indicate a further slowing down of wind. Given that the wind is now dying down in the city and people are out bursting leftover crackers yet again, there is almost a cent per cent certainty that a smog alert should be sounded before I start making my breakfast in the morning.   

I am praying for rain, while the Delhi administration is requested to roll out emergency action ASAP.

Graph 1: Rolling 24hour average PM2.5 concentration in the city has been in severe AQI category since Diwali night


Graph 2: Hourly average PM2.5 concentration in the city has started to not dissipate as the wind speed declines

Delhi entering into ICU again

You name it, we have it. All pollution sources in an almost-closed atmosphere with nominal ventilation. The Delhi-National Capital Region is witnessing a massive build-up of air pollution.

The wind speed in many areas is a mere 1 kilometre per hour, meaning it will take a lot of time for the atmosphere to disperse the air pollutants. In common parlance, it can be said that city is emitting in a closed room with almost insignificant ventilation.

On Tuesday, the levels of PM2.5 were hovering around 90 to 100 microgram per cubic metre. Post-Diwali, the levels are hovering close to the ‘severe’ range, or are remaining in the ‘very poor’ range.

The implications: the pollution level may cause respiratory illness among people on prolonged exposure. People having lung and heart diseases are at major risk. In areas with severe levels, the health impacts may be experienced even during light physical activity.

The effects will be even on healthy people. SAFAR has informed that the contribution of external biomass burning, mainly in neighbouring states has contributed 25 per cent to PM2.5 on October 29, 2019 and it will further increase up to 29 per cent by October 30.

Clearly, the states and Central government have collectively failed to bring a solution on the ground to reduce agricultural residue burning.

While the Delhi government and enforcement agencies have been directed to take strict action on instances of pollution, a lot still needs to be done in Delhi and intensely in its satellite towns.

The odd-and-even scheme can bring some relief if implemented well and people opt for public transport, carpooling, sharing mobility but it is not the permanent solution.

The comprehensive action plan notified by the Union Ministry of Environment, Forest and Climate Change for Delhi-NCR should be thoroughly implemented to bring a lasting solution.


Graph: PM2.5 concentration in Delhi inches close to emergency mark

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