Come winter and the hot topic of discussion is Delhi’s deteriorating air quality and the risks that Delhiites face owing to the dipping air quality index (AQI).
On Thursday morning, the residents of the national capital woke up to a very poor AQI, with Anand Vihar recording a ‘severe’ AQI of 405 at 7 am. This comes after Delhi witnessed a day of poor air quality on Wednesday — with the 24-hour average AQI at 4 pm being 271, improving from 303 at 4 pm on Tuesday. It was 312 at 4 pm on Monday, the day of Diwali.
An AQI between zero 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’.
Also read: How Cyclone Sitrang helped Delhi record its cleanest post-Diwali air since 2015
While the situation is exacerbated in winter, experts point out that air pollution is a constant struggle in Delhi and, in fact, the residents of the capital rarely breathe good or clean air.
Here’s a closer look at just how bad is the Delhi air situation and what contributes to making it the ‘polluted capital’ of the country.
Delhi’s air woes
A look at the AQI in the capital will reflect that Delhi rarely has a ‘good’ day. This means that the AQI in the capital is rarely between zero and 50.
In this year itself, the area has recorded only two ‘good’ days — first on 16 September and then again on 9 October. On both these days, the AQI reading was 47 on the back of overcast skies, intermittent rain and breezy conditions.
Prior to September, Delhi hadn’t recorded a single ‘good’ day in the year 2022. In the first six months, government data revealed that it had recorded seven ‘satisfactory’ and 47 ‘moderate’ air quality days. The data further showed that city saw 105 ‘poor’, 21 ‘very poor’ and one severe air quality day in the same time period.
In 2021, the situation was no better. Delhi only recorded one such day due to unexpected rain on 18 October.
In 2020 when the world was locked down owing to COVID-19, Delhi managed to record five ‘good’ days. Four of the five ‘good’ days were in August when it was raining and there was good wind speed. In fact, on 31 August, Delhi recorded its lowest-ever AQI reading at 41.
Graphic: Pranay Bhardwaj
The year 2019 only recorded two ‘good’ air days — on 18 and 19 August when the AQI reading was 49. In 2018, not a single day made the cut.
It was in 2017 that Delhi saw its first ‘good’ day since the launch of the index. In that year, the capital saw 30 and 31 July as ‘good’ air days with AQI readings at 43 and 47 respectively. The prior two years — 2015 and 2016 — recorded no ‘good’ air days.
This clearly shows that air pollution in the capital is not a seasonal issue, but a year-long struggle.
Causes for Delhi’s bad air
So, what makes Delhi’s air so hazardous? Experts cite observe there are a few reasons that make breathing difficult in Delhi.
The two biggest factors contributing to Delhi’s poor air are construction activity and transport.
In fact, the Supreme Court had said last year that stubble burning by farmers in the neighbouring States was not the major cause for air pollution in Delhi; rather, it was urban factors such as construction activities, industrial emissions and vehicular pollution.
There are several studies that have also been done that find that construction and vehicles are the real culprits of air pollution.
In 2021, a study by the think tank Centre for Science and Environment (CSE) said that vehicles contributed to more than 50 per cent of Delhi’s pollution between 24 October and 8 November last year.
The study also stated that industries contributed 9.9-13.7 per cent of air pollution while construction activities accounted for 6.7-6.9 per cent of pollution in the national capital.
Goyal (2014) of Centre for Atmoshperic Sciences, IIT Delhi, also stated that the largest contributor of air pollutant emissions in Delhi is found to be vehicles.
Vehicles are the largest contributor of air pollutant emissions in Delhi. AFP
The per capita registration of high emission vehicles in Delhi is reportedly the highest in India; more than half of the city’s middle-class homes have two or more cars. This has led to vehicle population to treble since 2007. Cramped residential quarters around the industrial zones not only lead to traffic congestion but also stop the polluted air from escaping.
Experts note that old vehicles release 4.3 per cent of all particulate matter in Delhi. In fact, it has been shown that a BS-I diesel car (pre-2000) emits 31 times more particulate matter than a BS-VI diesel car. A BS-II diesel car (pre-2005) emits 17 times more PM than a BS-VI counterpart.
Construction is another big culprit when it comes to air pollution. Experts note that construction and demolition cause huge amounts of dust — contributing to most harmful pollutants in the city’s atmosphere.
Environmental and medical experts have noted that the city’s construction sites, and the production of the raw materials that feed them — such as bricks and concrete — are an outsized contributor to the foul air. Poor building standards and antiquated practices compound the problem.
A worker uses a anti-smog gun to control dust at a construction site in New Delhi. Poor building standards and antiquated practices make construction a highly-polluting activity. AFP
Also, Delhi simply lacks the capacity to safely process the amount of construction waste it produces. A senior environmental engineer at the Delhi Pollution Control Committee was quoted as telling The Guardian that current facilities allow for about 1,000 tonnes of waste to be processed per day, but the city produces an estimated 3,600 tonnes.
Also read: What are anti-smog guns and how effective are they in reducing pollution?
A third major contributor to Delhi’s air woes is the open burning of garbage at landfills and in neighbourhoods.
Delhi has three major landfills, Bhalswa, Okhla and Ghazipur, where the city’s waste is dumped each day. According to data, the capital produces close to 10,000 tonnes of waste each day — way beyond the capacity of these sites.
Workers operate excavators amidst garbage at the Bhalswa landfill in New Delhi. AFP
The burning of garbage worsens the air quality and also releases dangerous toxins into the air, which has attributed to a rise in heart and lung diseases.
Other sources of pollution are stubble burning and firecrackers burnt during Diwali.
Is there a way out?
Delhi’s air pollution can be checked. However, the authorities and residents both have to come together to fight this problem.
Some long-term measures that can be suggested for cutting down the extreme pollution levels include, imposing a ceiling on number of vehicles per household, controlling diesel vehicles registration, using of CNG engines for public transport and phasing out old commercial vehicles, restricting and regulating construction activities, efficient management of garbage and banning of smoke generating fireworks in all social events.
With inputs from agencies
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