Every October, as the rains recede, Delhi prepares to choke on poisoned air that sees a periodic surge for three months in the year starting around Deepawali (Diwali), in late October. This year, the Delhi Government even asked the public for suggestions on how to cope with these recurring foul-air episodes. Ultimately, pollution levels ended up being particularly bad this year.
Particulate matter below 2.5 microns in diameter (PM2.5) concentrations — which decide the impact of air pollution on people's health and reduced visibility as the main component of the 'haze' seen on pollution-heavy days — ranged above 500 µg/m3 at their peak. That's nearly ten times the national standard average of 60 µg/m3 over a 24-hour period, and twenty times the World Health Organization’s recommended guideline for PM2.5.
Gurugram’s air quality was 17 times poorer than the prescribed safe limit by the World Health Organisation (WHO). Image: Vinay Gupta
Delhi’s extreme air pollution problem, which worsens in winter, is not a new one. In the last two decades it has received more attention than any other urban air pollution problem in the world — but efforts to tackle it have been in vain.
Attempts to tackle Delhi’s woeful air quality
To understand the contours of Delhi’s air pollution problem, five detailed studies were done in the last decade. During this time, 35 automatic air quality monitoring stations — each costing over Rs 1 crore — were installed, generating online data on air quality indicators every 15 minutes.
Conversion of public transport vehicles to run on CNG, and the introduction of better quality fuel began in the 1990s. Today, Delhi’s fleet of 5,500 buses is the largest CNG-powered fleet anywhere in the world. Another 1,000 CNG buses and an equal number of electric buses are to be added by the middle of next year.
The use of Bharat Stage VI (BS-VI) fuel — which has one-tenth the sulphur content in fuel supplied today — will be a mandatory norm in India's transportation sector from the mid-2020s. It has already been made available in Delhi, as well as 19 surrounding districts in Haryana, Rajasthan, and UP since end-September.
Emission standards for BS-VI compliant vehicles. Courtesy: Airveda
Going back just twenty years, Delhi didn't have a metro. Today, with a 389-km-long route and a billion riders per annum, the Delhi metro has jumped to become the sixth-largest metro in the world.
The metro was meant to reduce private vehicles on Delhi’s roads. Instead, as some bus commuters shifted to the metro, they made way for more private vehicles on the road, proving that the Jevon’s paradox is well at work in Delhi. To that end, Delhi’s air pollution woes still persist.
Data records of Delhi’s air quality indicate that hourly averages of PM2.5 levels have regularly peaked in the range 500-1,000 µg/m3 for over 10 years, specifically in October-November months, with no sign of abatement.
The Delhi Metro hasn't contributed to curbing air pollution as much as the government intended for it to. Image: Getty
To stave off the foul air nightmare this winter, several new air pollution mitigation measures have been introduced this year. Fifty-four WAYU air filters that can suck dust and burn hydrocarbons in their surrounding air are being installed at some traffic junctions.
The coming months will see multi-pronged initiatives by @moefcc & @IndiaDST to address air pollution in cities. #WAYU is a result of Env. Minister Dr Harsh Vardhan challenging Science & Technology Minister Dr Harsh Vardhan - science resolves an urban phenomenon. @CSIR_IND pic.twitter.com/gS4cQQC2KO
— Dr Harsh Vardhan (@drharshvardhan) September 26, 2018
After introducing it twice in 2016, the odd-even rule, which allows cars with certain number plates to run on alternate days, was re-introduced recently. None of these measures helped — including the contentious odd-even rule — and PM2.5 concentrations remained above 400 µg/m3, making Delhi’s air unbreathable.
The Supreme Court-appointed Environmental Pollution Control Authority pushed for a temporary ban on non-CNG vehicles, i.e., 85 percent of registered private vehicles in Delhi, but was opposed on grounds that Delhi’s woefully inadequate public transport system would break down completely if this were done.
Scientists have begun replacing many of these pilot project air purifying units in Delhi with ones, which, apart from promising almost double the efficiency in cleaning air. Image: ESS Enviro
Engineering controls have failed
A senior functionary of the Central Pollution Control Board once remarked, "We have the same technology as that of developed countries, so why is Delhi’s air quality so poor?"
To answer that question, we can't go without asking whether those responsible for environment management missed reading the Delhi air quality problem correctly, and failed to provide workable solutions that are appropriate for Delhi.
Take the case of the expensive online monitoring stations that were installed in Delhi. Information Theory 101 tells us that online information is useful when immediate action can be taken. For example, when there is a process upset in a reactor, the operator takes corrective action immediately. On days that Delhi had high air pollution levels, did the online data help in diverting vehicular traffic away from polluted areas, thus reducing air pollution loads in these areas? Or were commuters diverted from surface transport into the metro, reducing their exposure to air pollution? Apparently not!
Why were passive samplers not made regulatory instruments? Despite a proven record of their ability to provide decision-support information just as well as automatic stations do, passive samplers can do it at a cost that's 3 times lower in order of magnitude. Or is this a classic syndrome of "big toys for the big boys" at work, where those responsible for environment management make-believe that big toys can do the job best?
A passive sampler. Image: Author provided
Delhi’s rapid vehicular growth and continued poor air quality in the last two decades quite clearly indicates that the Delhi Metro, while facilitating public transport, did not contribute to improving the city’s air quality since it didn't wean enough private vehicle riders away from roads. The Delhi Metro has, in fact, added to pollution loads as the last-mile connectivity from metro stations to onward destinations is largely by autos instead of non-polluting modes like walking and cycling.
If the last-mile ride were by battery-operated autos instead, the point of pollution is transferred from the prime mover to the power plant, where air pollution causes significant crop yield losses and respiratory illness in a radius up to 25 km around thermal power plants. This is an issue that has, so far, remained unaddressed. If the autos were fossil-fuel-powered, it does nothing if not harm to Delhi's air pollution woes.
Are CNG and low-sulphur containing fuels helpful?
Yes, they have reduced SO2 concentrations in Delhi, but not that of nitrogen dioxide (NO2) and PM2.5 concentrations.
The hidden cost of moving to cleaner fuels is the large investment refineries made to remove additional sulphur from crude oil, just as vehicle manufacturers did in fine-tuning existing engines.
The National Environmental Engineering Research Institute (NEERI), which fabricated the WAYU air filters recently installed in Delhi and several other metros in India, claim that these machines have an effective pollution cleaning area of 500 m2, i.e., an area of 25 m x 20 m, which effectively makes it a large room purifier. The claimed filtering efficiency of ~80 percent for PM2.5 and ~40-50 percent for hydrocarbons in open spaces is still to be demonstrated.
Even if that efficiency were achieved, how many hundreds or thousands of such machines would Delhi require? How often would the filters have to be replaced in Delhi’s choked air? And is the cleanup cost just the price of the machine, i.e., Rs 60,000, or should running and maintenance costs be added?
The cost of underestimating particulate matter pollution is asphyxiation and death itself. Image: NW18 Creative
The efficacy and cost-benefit of the measures taken to control pollution in Delhi are yet to be adequately evaluated. Such an evaluation must also be communicated in a language that the general people can easily understand. Linking Delhi’s air quality to incidence and prevalence of respiratory illnesses like asthma is a better means of communicating air quality impact to the public than pollutant concentrations in µg/m3, or air quality as AQI for that matter. This would also help people understand to what extent air quality standards have helped in improving environmental health, which is increasingly becoming a public health problem too.
In a rare moment of truth, a former Ministry of Environment official admitted three years ago that, “We have failed to control Delhi’s air pollution.” So what went wrong? Delhi’s environmental managers followed “handed-down wisdom” from North countries that used engineering control systems, consequently technological solutions, to control their pollution problems after having polluted their cities.
Two factors impede engineering control systems from delivering tangible results in Delhi. First, the average wind speeds in tropical countries are significantly lower than in temperate countries. For example, Delhi’s annual average wind speed is ~2.6 m/s, whereas London’s is double that. Ground-level pollution concentration is inversely proportional to wind speed. Given the same pollution load, Delhi’s ground-level pollution concentrations will be twice that of London.
A map of the average wind speeds in various countries and regions around the world. Image: Author provided
Moreover, Delhi and much of North India have bad inversions in winter. Given this climatic disadvantage, the cost of using engineering control systems is Delhi prohibitively high, that is if it works at all.
Additional pollution loads and adverse meteorology contribute to high pollution levels in October-November. Deepawali crackers and burning stubble from Kharif paddy harvests in Punjab, Haryana and Western UP cause a greater pollution load for about 2-3 weeks in these months. Moreover, a post-monsoon wind shift blowing from the south-east to north-west waft pollutants from stubble burning in North India directly into Delhi before carrying them further south-east along the Indo-Gangetic plain.
Also read: Stubble burning costing India $152.9 billion in health expenses over five years
October-November have the lowest wind speeds (<1 m/s—see fig) in the year. Moreover, they also have the greatest frequency of temperature inversions. These meteorological phenomenons greatly impede pollution dispersion, and along with the higher loads that Deepawali and stubble burning cause, are responsible for Delhi’s post monsoon air pollution woes.
And this has been happening year after year.
Residents take an early morning walk in smog in Delhi. AP
The second factor that works against engineering control systems is Delhi’s city structure. Delhi is two cities rolled into one — an older one built much earlier, with narrow streets meant for animal carts and pedestrians; and a newer one built more recently, with broad streets for the high-density flow of fossil-fuel-powered vehicles.
Like most other cities in developing countries, Delhi is a semi-fossil fuelled city that cannot be changed easily. The old city’s narrow streets act as box traps for air pollutants; above-ground metro decks in some parts of the old city only makes pollution trapping worse.
As of the year 1900, European and North American cities were non-fossil fuelled cities. In the 100 years that followed, they urbanized rapidly, from 17 percent to 75 percent, building overwhelmingly fossil-fuel-powered cities. It takes upwards of 0.3 Million tonnes of oil equivalent (Mtoe) in energy and Rs 2,000 crores in infrastructure to transform just 1 km2 of greenfield landscape (or to convert a semi-fossil fuel-driven one) into a fully fossil-fuelled city.
A world without cars, planes, ships and factories powered by fossil fuels will need to be a reality in 40 years to have a realistic hope of keeping global warming below safe levels, scientists claim. Image: Stock photo
The Europeans and Americans siphoned money to build their cities from their hinterlands, colonies and through unequal exchange with developing countries. Developing countries will find it hard-pressed today to make such large investments for converting their cities into fully fossil-fuelled ones, and therefore will have to be content with their cities remaining semi-fossil fuelled cities.
Old Delhi’s narrow streets, the addition of ~70,000 new vehicles per annum to the existing ~1 crore registered vehicles in Delhi, low wind speeds and adverse meteorology make a perfect recipe for high pollution loads and poor dispersion that contribute to Delhi’s filthy air.
There's little that engineering controls can do to remedy the situation, and little, if anything, can be done will be prohibitively expensive. The use of engineering controls in Delhi is akin to a walker having to walk ever faster to remain in the same place.
A civic worker, wearing an anti-pollution mask, sweeps the road amid heavy smog in New Delhi on 15 November 2019. The thick layer of toxic smog engulfed Delhi as pollution levels continued to remain in the 'severe' category for the fourth consecutive day. Image: PTI/Arun Sharma
Administrative controls—more likely to work?
Studies on Delhi’s air pollution have placed emissions from transportation as the largest contributor (18-39 percent) to PM2.5 concentrations, followed by edaphic source (soil) dust (18-38 percent) and industry emissions (2-29 percent), let us deal with transport emissions.
Sector-wise sources of PM2.5 pollution.
A vast majority of trip modes in Delhi are by walk. Ironically, pavements and cycle paths get the least investment. In India of trips other than by walk and non-fossil fuelled transport modes, e.g., bicycles, almost 80 percent are by buses and trains and the energy expended by them is only 30 percent of the total transport sector energy expenditure. Whereas car trips constitute 8 percent of all trips but consume 40 of energy expended. The emissions of a person going by bus or train is ten times less than if he went by car.
If our past transport planning was responsible for this, surely there is now a need for a re-think on whether we have done things the right way to minimize emissions. And this includes retrofitting all of Delhi with CNG as a fuel.
Applying the philosophy of Occam’s Razor (avoid excessively complex solutions) to Delhi’s intractable pollution problem indicates that minimizing emissions if not eliminating them is a better solution than allowing pollution in the first place to later seek out clean up solutions. Administrative control methods, which use non-engineering measures to eliminate or minimize emissions, should be given priority over engineering controls. Transport emissions are very amenable to minimization through administrative controls by reduction of trip frequency and distance, and altering trip mode, first from private to public transport, and next from fossil-fuel-driven public transport to non-fossil fuelled transport like bicycles.
Reducing trip distance, for example, can be done in Delhi by mandating that schoolchildren use school buses to attend neighbourhood schools that are not more than 2 km from home. Neighbourhood schools are in vogue in several developed countries. If the average travel distance saved by each of Delhi’s 7.5 million schoolchildren is 8 km a day (assuming that 90 percent of these trips are by bus and 10 percent of them by cars), about 250 million litres of diesel/petrol cost (~Rs 1,800 crores per year) would be saved. The reduced emissions would also improve air quality in Delhi significantly.
Use of bicycles can be encouraged by laying down many bicycle pathways, and cycle parking bays at metro stations, perhaps even allowing bicycles onto the metro. These measures will help, to a reasonable extent, in replacing autos with bicycles for last-mile connectivity to metros stations, thereby reducing emissions. If 5 percent of metro riders switched from autos to bicycles for their last-mile connectivity distance of 6 km each day, about 7.5 million litres of diesel/petrol, costing Rs 50 crores, would be saved each year, on top of seeing an improvement in Delhi’s air quality.
Green cities of the future are both ecologically and economically resilient — they are made of healthy, liveable neighborhoods where the benefits of nature are available to all residents. Image: The Nature Conservancy
Another way of reducing transport emissions is a vehicle (bicycles, 2-wheelers, cars)-share scheme. A subscriber to such a scheme can pick up a vehicle from any point and drop it off at another point in the scheme’s jurisdiction. Access to a vehicle is gained by using a common key or by punching a password to a server through a mobile phone. The vehicles could be managed and tracked using GPS trackers and personal identification numbers. Over 1,000 cities around the world, including four in India, operate schemes like these. Car-share systems are popular in many major cities like New York, where a variation of this scheme is also seen: vehicle-pooling, which is relatively easier to implement on a smaller scale/trial basis.
Emission can also be reduced by declaring certain parts of the city, like Connaught Place today, as "vehicle-free" zones. As a public service, a few electric vehicles for senior citizens, and a cycle share scheme for the general public may be allowed. Vehicle-free zones aren't a new concept, even for cities in India. Vehicle registration and parking fees in inner-city areas could be hiked, as has been done in many parts of the world. One-way streets could also be increased significantly.
If annual carbon and energy footprinting is carried out by all organizations — government ministries and departments (central and state), enterprises (corporations, firms, shops, and establishments) mandated by law, just as financial audits are today, and footprints were reduced by 3 percent per year, Delhi could halve its carbon and energy footprint in 20 years.
With exceptions, Connaught Place in Delhi is a vehicle-free zone.
Implementing administrative controls requires public will
Can the present environmental authorities (Environmental Pollution Authority, Delhi Pollution Control Committee, Ministry of Environment, Forests and Climate Change) implement such measures? Oh, I doubt it. Their jurisdiction, as defined by environmental laws, is narrow and confined to pollution control (read 'end-of-pipe abatement').
These environmental authorities require the cooperation of other departments to implement the above suggestions, and obtaining that is an uphill task. The more important question is whether the Union and the Delhi governments have the will to clean up Delhi. So far, Delhi’s citizens have been had such administrative control measures implemented by collectively pushing for them. Delhi’s citizens wishing to have cleaner air will simply need to fight for it.
In the long-term, the solution is de-growth
But the story does not end there. Administrative control of emissions is a transient measure that can minimize pollution loads, but cannot control Delhi’s adverse climate and the city’s structure — the city’s environmental nemesis. If the city is allowed to expand, its pollution load will increase, and administrative controls, however good they may be, won't save Delhi from becoming hell on Earth.
Air pollution affects the health of children and infants the most. Image: Antara
Mathura, a small city located 100 km south of Delhi has an interesting tale to tell.
Not unlike Delhi, it has low wind speeds and winter inversions that are worse than Delhi’s when put in perspective. A paper by Padmanabhamurthy and Mandal published in Mausam, the India Meteorological Department’s journal, in 1979 warned that Mathura has a "high pollution potential". Yet, the UP Pollution Control Board website reports the Air Quality Index (AQI) for Mathura to be moderate (138-149) in October 2019, when air quality was at its worst in years.
Delhi’s AQI for the same period was poor (average of 239), and had even dipped to the severe category (400-500) on occasion. Mathura didn't suffer the same fate of poisoned air that Delhi did because of its relatively small pollution loads.
Engineering control measures have not saved Delhi from the ravages of air pollution despite expensive cleanup measures adopted so far because of the low pollution load carrying capacity the city has. Administrative control measures, which help curb pollution loads, might be a better way to control air pollution in Delhi but require massive public support in the face of stiff resistance from Delhi’s environmental managers who are entrenched in engineering control methodology.
In the long run, even administrative controls will not help a growing Delhi, but will it fall into the trap of the Jevon’s Paradox. Stopping Delhi’s growth, capping its emissions, and moving towards de-growth can de-toxify Delhi’s atmosphere.
The author has worked with the United Nations Environment Programme as an environmental engineering consultant, and was a faculty at BITS Pillani.
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